Windows – nsinstall: Bad file number error on Vista

I'm attempting to build Firefox on my Windows Vista Ultimate machine. I keep getting the following error:

nsinstall: Bad file number

I've read that this error is caused because of UAC in Vista. Here are the two articles that lead me to this conclusion. https://wiki.mozilla.org/Penelope_Developer_Page#Windows_Vista and http://www.kevinbrosnan.net/mozilla-build-error-nsinstall-bad-file-number

Using the standard "Run as Administrator", I've attempted to redo my build but I get the exact same error. I also started a normal command prompt as admin and then went to the batch file in mozilla-build (start-msvc8.bat) and ran it. Still, same error at the same point.

Any other insights on how I might either get around this error or perhaps something else is causing the error?

Note: I also posted something here in the hopes to get topic-specific help but I've not heard a peep… After I posted that I found the info on nsinstall. Anyway, I prefer SO so I thought I'd try here…

Update: I've attempted to completly disable UAC to correct the problem as is suggested by cnemelkasr. I've received the exact same error. This new knowledge is making me think that a file or folder is missing… Does anyone who has experience with NSInstall know what the given error — Bad file number — might mean? I figure it might be referring to a file handle…