When you run a batch file as administrator under windows vista and 7 the current directory gets set to C:\windows\system32. This can prevent your scripts from working correctly if you use relative paths.
To fix this problem, include these two lines at the top of your .bat script:
@cd /d "%~dp0"
This will change the current directory to the location of the .bat file.
How it works:
@setlocal enableextensions - controls the visibility of environment variables
] and enables cmd extensions
@cd /d "%~dp0" - Changes the current directory to %~dp0 which is a special batch parameter
] that expands to the drive and directory that batch file is located in.
%0 expands to the full path and file name of the batch file, adding the ~dp modifier in the middle to make %~dp0 reduces the %0 value to just the drive and path.