Windows 7 batch script behavior difference vs. XP

One of my clients is in midst of migrating a few reporting applications over from XP to Windows 7 and called me to assist in looking at an issue where they could not register some dll components.

I took a look at the Windows batch file and it contained lines like:
copy xxx.dll "%WINDIR%\System32"
regsvr32 xxx.dll

When I launched the script, it complained about access denied, so I right-clicked the script and ran it as administrator. But running as administrator, it complained it cannot find the xxx.dll.
That's when I noticed the execution directory became c:\windows\system32 when I executed the script as administrator, even thought the script was located in another drive letter and path.

The solution was to update the batch file as follows:
copy <path>\xxx.dll "%WINDIR%\System32"
regsvr32 xxx.dll

and then run it as administrator.