Ok.. I know this might seem rediculous, because I am NOT a DOS guru, but
Just add the follow to the top of the BAT file.
C:
When I open the DOS prompt on my networked machine, it is directed to the
Z: drive.
When I open it locally with a BAT file it defaults to C:\Documents and Settings etc...
I created a test BAT file and put in Z: and it redirected to that drive before it did anything else.
Try it..
Just type in C: on the very first line of your BAT script.