As you have pinpointed the error to a problem in the autoexec.bat file, could you post the contents of this file for us all to see - the problem may just leap off the page for one of us :)
I seem to remember that if you go to Start > Run, and type
there is a tab that displays the contents of the autoexec.bat file. Copy and paste this to the Forum.
Please remember to add an extra blank line between each line of autoexec.bat when you post it here, as it makes it a lot easier to read.