Go to your PHP config file (Typically at C:\PHP) and open the php.ini file (use notepad or something like
Programmer's notepad). Scroll down to the "upload_tmp_dir" variable (I suspect this is your problem but not 100% sure) and set it to a folder that has write permissions.... I fought forever with this and then I realized it was a stupid permissions problem.
Good Luck... PHP is tricky (I like ASP.net better)
--Chris