Error Message useless

[Tower Ty]

tango.core.Exception.IllegalArgumentException: Argument not valid

This message from the compiler is just bloody useless 
Where do you go in a 200 line program?

All I can see is go to each line that might be a cause and comment it out ,try to compile it again and if no good do the next one .

Some lines just can't be done anyway .

How hard could it be for you experts to add some detail to the error huh ??