I also noticed that on a machine having this issue that mfevtps.exe is consuming 95% of the CPU when I visit the web sites mentioned above. This is a Windows XP Pro SP3 machine running VSE 18.104.22.1687, HIPS 22.214.171.1249, and McAfee Agent 126.96.36.1990.
Still having issues after re-installing Firefox ESR 10.0.6 with a newer version of the Flash Plugin 11.3.300.271. Another curiosity is that when an Admin user is logged in Firefox does not crash on the same machine where a regular user running Firefox will crash. Still when I disable Host IPS no crashes are reported.