help! outlook 2003 on windows server 2003 problem.

[rpm087]

we have two computers in our data center (windows server 2003, running outlook 2003) that customers can log into to access their email from anywhere, and we've been receiving complaints that whenever they try to attach a file, they receive an error message that says "this operation has been canceled due to restrictions in effect on this computer. Please contact your system administrator." Whenever we log on, even internally as the administrator, we get the same message. It seems to still send the attachment, but its a minor inconvenience to deal with the error message every time you attach something. I've been searching for an answer, but the only problem I can find with that error message is when people click on links in their email, the browser doesn't open, and it gives them that error message. I tried clicking a link and it worked fine, so that's not the problem. I went ahead and tried the fix which is setting the internet explorer as default but that didn't resolve the problem. We're completely stumped as to whats causing this error. any help is greatly appreciated.

[MidiMagic]

This is a security setting, in either Outlook or Internet Explorer.

[DimaYasny]

http://www.informit.com/articles/article.aspx?p=366893&seqNum=7