The Symposium Web Client server checks for IE version 5.5 or 6 on the client PC. It refuses to cooperate if it sees V7.
That will hopefully be fixed soon in a Service Update from Nortel.
Meanwhile there is a workaround you can use from Microsoft that will spoof version 6.0.
You can get the details here:
I found that there are some additional ActiveX security settings in IE 7 that I had to change also. In addition to the security settings you should already have set you will need to change this:
In Tools, Internet options
Select Security tab
Select Trusted sites icon
Select Custom level
"Allow scriptlets" - set to enable
So you probably want to avoid IE 7 for general use but it works fine for me with the workaround.
IE 7 seems okay with CallPilot Manager (no workaround required).
I don't have Element Manager, NRS or MIRAN so I can't comment on those.