error in Win7 but not XP

I have a script that runs under Windows XP but not under Windows 7.  Both are work computers.

The error I get when running my script under Windows 7 is:

Line 8327

(path to my script aplet here)

ERROR: subscript used with non-array variable

can anyone tell me what this means so I can make things work under the Windows 7 OS. My script only goes up to line 1153. IF you need to see all my code I can post that.

thanks.