Can Someone tell me what wrong with this program please :(

1. mon = peripheral.wrap("left")
2. function lineBreak()
3. x, y = mon.getCursorPos()
4. if y ~= 1 then
5. y = y + 1
6. end
7. mon.setCursorPos(1, y)
8. width, height = mon.getSize()
9. mon.write("+" .. string.rep("-", width - 2) .. "+")
10. end
11. function printString(sString)
12. x, y = mon.getCursorPos()
13. y = y + 1
14. mon.setCursorPos(1, y)
15. mon.write(sString)
16. end
17. function printStringCentre(sString)
18. x, y = mon.getCursorPos()
19. y = y + 1
20. mon.setCursorPos(1, y)
21. width, height = mon.getSize()
22. nStringCentre = math.floor(string.len(sString) / 2)
23. nMonitorCentre = math.floor(width / 2)
24. x = math.floor(nMonitorCentre - nStringCentre)
25. mon.setCursorPos(x, y)
26. mon.write(sString)
27. end
28. function printStringRight(sString)
29. width, height = mon.getSize()
30. x, y = mon.getCursorPos()
31. y = y + 1
32. x = math.ceil(width - string.len(sString))
33. mon.setCursorPos(x, y)
34. mon.write(sString)
35. end
36. function scrollText(tStrings, nRate)
37. nRate = nRate or 5
38. if nRate < 0 then
39. error("rate must be positive")
40. end
41. end
42. nSleep = 1 / nRate
44. width, height = mon.getSize()
45. x, y = mon.getCursorPos()
46. sText = ""
47. for n = 1, #tStrings do
48. sText = sText .. tostring(tStrings[n])
49. sText = sText .. " | "
50. end
51. sString = "| "
52. if width / string.len(sText) < 1 then
53. nStringRepeat = 3
54. else
55. nStringRepeat = math.ceil(width / string.len(sText) * 3)
56. end
57. for n = 1, nStringRepeat do
58. sString = sString .. sText
59. end
60. while true do
61. for n = 1, string.len(sText) do
62. sDisplay = string.sub(sString, n, n + width - 1)
63. mon.clearLine()
64. mon.setCursorPos(1, y)
65. mon.write(sDisplay)
66. sleep(nSleep)
67. end
68. end
69. mon.clear()
70. mon.setCursorPos(1, 1)
71. lineBreak()
72. printStringCentre("|General stuff|")
73. lineBreak()
74. printString("")
75. lineBreak()
76. tScrollText = {}
77. tScrollText[1] = "Fact:"
78. tScrollText[2] = "Rainbowdash is NOT a girl!"
79. tScrollText[3] = "Fact:"
80. tScrollText[4] = "Grahamcraft is the best server ever in the world"
81. lineBreak()
82. printStringCentre("Rules")
83. lineBreak()
84. printString("1, Do not grief**")
85. printString("2, Do not disrespect admins*")
86. printString("4, Do not lie about donating to the server**")
87. printString("5, Do not advertise other servers on ours***")
88. printString("6, Do not steal from others**")
89. printString("7, No pvp in this world")
90. printString("8, Do not ignore these rules, READ THEM NOW!")
91. printString("9, Play fair and have fun!***")
92. lineBreak()
93. printString(" * = warning")
94. printString(" ** = depends how serious")
95. printString(" *** = Instant ban")
96. x, y = mon.getCursorPos()
97. y = y - 1
98. mon.setCursorPos(1, y)
99. scrollText(tScrollText)

local mon = peripheral.wrap( "left" )
term.redirect( mon )


-- all your code here


term.restore()

mon = peripheral.wrap("left")
width, height = mon.getSize()
function lineBreak()
    x, y = mon.getCursorPos()
    if y ~= 1 then
		    y = y + 1
    end
    mon.setCursorPos(1, y)
    width, height = mon.getSize()
    mon.write("+" .. string.rep("-", width - 2) .. "+")
end
function printString(sString)
    x, y = mon.getCursorPos()
    y = y + 1
    mon.setCursorPos(1, y)
    mon.write(sString)
end
function printStringCentre(sString)
    x, y = mon.getCursorPos()
    y = y + 1
    mon.setCursorPos(1, y)
    width, height = mon.getSize()
    nStringCentre = math.floor(string.len(sString) / 2)
    nMonitorCentre = math.floor(width / 2)
    x = math.floor(nMonitorCentre - nStringCentre)
    mon.setCursorPos(x, y)
    mon.write(sString)
end
function printStringRight(sString)
width, height = mon.getSize()
x, y = mon.getCursorPos()
y = y + 1
x = math.ceil(width - string.len(sString))
mon.setCursorPos(x, y)
mon.write(sString)
end
function scrollText(tStrings, nRate)
nRate = nRate or 5
if nRate < 0 then
  error("rate must be positive")
end
end
nSleep = nRate
x, y = mon.getCursorPos()
    sText = "fds"
    for n = 1, #tStrings do
		    sText = sText .. tostring(tStrings[n])
  sText = sText .. " | "
    end
    sString = "| "
    if width / string.len(sText) < 1 then
		    nStringRepeat = 3
    else
		    nStringRepeat = math.ceil(width / string.len(sText) * 3)
    end
for n = 1, nStringRepeat do
  sString = sString .. sText
end
while true do
  for n = 1, string.len(sText) do
   sDisplay = string.sub(sString, n, n + width - 1)
   mon.clearLine()
   mon.setCursorPos(1, y)
   mon.write(sDisplay)
   sleep(nSleep)
  end
end
mon.clear()
mon.setCursorPos(1, 1)
lineBreak()
printStringCentre("|General stuff|")
lineBreak()
printString("")
lineBreak()
tScrollText = {}
tScrollText[1] = "Fact:"
tScrollText[2] = "Rainbowdash is NOT a girl!"
tScrollText[3] = "Fact:"
tScrollText[4] = "Grahamcraft is the best server ever in the world"
lineBreak()
printStringCentre("Rules")
lineBreak()
printString("1, Do not grief**")
printString("2, Do not disrespect admins*")
printString("4, Do not lie about donating to the server**")
printString("5, Do not advertise other servers on ours***")
printString("6, Do not steal from others**")
printString("7, No pvp in this world")
printString("8, Do not ignore these rules, READ THEM NOW!")
printString("9, Play fair and have fun!***")
lineBreak()
printString(" * = warning")
printString(" ** = depends how serious")
printString(" *** = Instant ban")
x, y = mon.getCursorPos()
y = y - 1
mon.setCursorPos(1, y)
scrollText(tScrollText)

general:46: attempt to get length of nil

function scrollText(tStrings, nRate)
nRate = nRate or 5
if nRate < 0 then
  error("rate must be positive")
end

nSleep = nRate
x, y = mon.getCursorPos()
    sText = "fds"
    for n = 1, #tStrings do
                    sText = sText .. tostring(tStrings[n])
  sText = sText .. " | "
    end
    sString = "| "
    if width / string.len(sText) < 1 then
                    nStringRepeat = 3
    else
                    nStringRepeat = math.ceil(width / string.len(sText) * 3)
    end
for n = 1, nStringRepeat do
  sString = sString .. sText
end
while true do
  for n = 1, string.len(sText) do
   sDisplay = string.sub(sString, n, n + width - 1)
   mon.clearLine()
   mon.setCursorPos(1, y)
   mon.write(sDisplay)
   sleep(nSleep)
  end
end
end

mon = peripheral.wrap("left")
width, height = mon.getSize()
function lineBreak()
	x, y = mon.getCursorPos()
	if y ~= 1 then
			y = y + 1
	end
	mon.setCursorPos(1, y)
	width, height = mon.getSize()
	mon.write("+" .. string.rep("-", width - 2) .. "+")
end
function printString(sString)
	x, y = mon.getCursorPos()
	y = y + 1
	mon.setCursorPos(1, y)
	mon.write(sString)
end
function printStringCentre(sString)
	x, y = mon.getCursorPos()
	y = y + 1
	mon.setCursorPos(1, y)
	width, height = mon.getSize()
	nStringCentre = math.floor(string.len(sString) / 2)
	nMonitorCentre = math.floor(width / 2)
	x = math.floor(nMonitorCentre - nStringCentre)
	mon.setCursorPos(x, y)
	mon.write(sString)
end
function printStringRight(sString)
width, height = mon.getSize()
x, y = mon.getCursorPos()
y = y + 1
x = math.ceil(width - string.len(sString))
mon.setCursorPos(x, y)
mon.write(sString)
end
function scrollText(tStrings, nRate)
nRate = nRate or 5
if nRate < 0 then
  error("rate must be positive")
end

nSleep = nRate
x, y = mon.getCursorPos()
	sText = "fds"
	for n = 1, #tStrings do
					sText = sText .. tostring(tStrings[n])
  sText = sText .. " | "
	end
	sString = "| "
	if width / string.len(sText) < 1 then
					nStringRepeat = 3
	else
					nStringRepeat = math.ceil(width / string.len(sText) * 3)
	end
for n = 1, nStringRepeat do
  sString = sString .. sText
end
while true do
  for n = 1, string.len(sText) do
   sDisplay = string.sub(sString, n, n + width - 1)
   mon.clearLine()
   mon.setCursorPos(1, y)
   mon.write(sDisplay)
   sleep(nSleep)
  end
end
end
mon.clear()
mon.setCursorPos(1, 1)
lineBreak()
printStringCentre("|General stuff|")
lineBreak()
printString("")
lineBreak()
tScrollText = {}
tScrollText[1] = "Fact:"
tScrollText[2] = "R"
tScrollText[3] = "Fact:"
tScrollText[4] = "G"
lineBreak()
printStringCentre("Rules")
lineBreak()
printString("1,")
printString("2,")
printString("4,")
printString("5,")
printString("6,")
printString("7,")
printString("8,")
printString("9,")
lineBreak()
printString("g")
printString("s")
printString("h")
x, y = mon.getCursorPos()
y = y - 1
mon.setCursorPos(1, y)
scrollText(tScrollText)

general:2:attempt to call index ?(a nil value)