When you created each user did you approve their account? Make sure each user is in the 'approved' status, otherwise they won't validate.

Open your web.config. Look at the <authentication> tag and check the mode. Is it set to "Forms"? If so, change it to "Windows". This *should* work. Note, however, that anybody running that page will...

Okay, i just saw a reference to Update Panel in your page code, but your upload control is declared outside of it. Use breakpoints and run your page in debug mode. Set break points inside of the...

FileUploader control does not work in the upload panel. In other words, it isn't Ajax compatible control. You need to do a regular postback through a trigger. It's a security constraint in the design...