Getimagesize() call failed (SOLVED)

I just had a strange problem that is now resolved and may help some people. I received the following error when I try to upload pictures with file sizes greater than 2 MB. All other pictures worked just fine.

"Call to getimagesize() failed in valid_image() for file"

I updated the php.ini entries (based on http://marc.theaimsgroup.com/?l=gallery-users&m=102589601604892&w=2) and I still got the same error.

The end solution was to grant write permissions to the C:\Windows\Temp directory for users IUSR_<Computer> and NETWORK SERVICE. The reason I had to go to this directory was because the upload_tmp_dir variable in my php.ini was blank so it uses this one as a default.