Trying to upload a picture (using Upload File), I get the following two errors (one or the other)

Got an error: CGI open of tmpfile: Permission denied (MT Error)

The Page cannot be displayed (Browser error page, with the usual instructions IE gives me)

The directory chosen is the LocalSitePath, images/uploads, which has write permissions (this is on a Windows server, which has full permissions for that directory for IUSR….however, the IWAM user does not…but I do not know what the IWAM user is, and the file permissions panel my ISP gives me does not list that account in the permissions list, so I can’t change it even if I wanted to)

Any ideas out there?