Strange URL for web project

[Jami Bradley]

Hi all,

We have several web service projects within a single solution. Occasionally something will change
and one of the projects won't load. I've spent a few days tracking this down and the reason it
doesn't load is the URL is changing.

We have a IIS virtual directory pointing back to our code (we don't keep the code in inetpub/...!)
and the project folder is one of the following:
http://localhost/VirtualDir/xxx
http://localhost:/VirtualDir/xxx (note the colon without a port number)

Now, the problem is that some users can't load it without the colon, and some users can't load it
with the colon.

Does anyone have an idea what might be triggering this and why it is a problem?
TIA,

Jami