.NET Framework Prevents login to Rabbit

We have been using the RCM3200 modules successfully for three years. We program using Dynamic C v9.21.

Our application uses the Rabbit web server for configuration accessed via Internet Explorer on a PC. Recently our customers have been using PCs with Microsoft .NET Framework 3.0/3.5 installed for other applications running on the laptop. This has interfered with the ability to access the Rabbit web server, ie the web server login box does not appear when accessed from Internet Explorerer. In fact no web pages appear at all from the Rabbit. Other web servers can be accessed work just fine. If we use Firefox it works OK.

When .NET Framework 3.0/3.5 is uninstalled, Internet Explorer can login to the Rabbit and access its web pages just fine. Prior to this, 2.0 was installed and it worked just fine also. It appears that something bad happened when Microsoft went from 2.0 to 3.0/3.5.

Anybody else seen this ?