[Calculator]Error: string expected, got table

I coded a little calculator…well i tried it. The Problem is at the function TaschenrechnerZahlen.
I want that the numbers , which were typed, added to a table, which is used to print and calculate with. But i get the Error:"String expected, got table". Hope you can help me :)/>

http://pastebin.com/H3jDvUtK

that is because a table is something that cannot be printed. try using table.concat instead.

write( table.concat( tableName, ' ' ) )

where the ' ' is the separator between each element in the table.

Thanks. Its fixed