WebCT Campus Edition 6 does not behave very well when the browser you are using has a popup blocker running. Most all browsers today have a popup blocker feature, and you can have a popup blocker installed on your machine AND use WebCT CE 6, but it really seems to be the blockers that come with the 'toolbars' that cause the largest problems.
What kind of problems? Usually they are the kind of problems where at the moment they are trying to do something that requires the popup (like opening the File Browser or creating a message for discussion/email), they will receive a message like 'you have no access or permissions' when all reason suggests that they should.
Toolbars, for those who do not know, are those extra rows of buttons and pictures you may find near (usually directly below) the Address bar in you browser (see example below). There are many of them, but the most popular from my experience appear to by those distributed by Google and Yahoo. For most of you, especially those who have the Yahoo toolbar, you will have absolutely no recollection as to how that 'got there.' Oftentimes it piggybacks on another application or update you DID intend to install.
The most noteworthy offender is Macromedia (or is it Adobe) Flash Player. It is a free download that has [relatively] frequent updates. Each update, if you are not careful, will install the toolbar. Of course if you do not have it already, then you do not receive a second. However, if you have deleted the toolbar program (easy to do), the next update can again put it back.
I use -- and enjoy having -- the Google toolbar. However, the popup blockers always start 'on.' I turn them off, and leave the Internet Explorer one on. I then add the WebCT site (actually I add '*.institution.edu' where the institution is yours) as a trusted site.