Unable to run Panda Activescan 2.0 on demand

Hello ,
I'm attempting to run this on-demand scan in Firefox 3.55 and Windows 2000.
The plugin downloads and installs. The process starts, but never progresses
beyond 0%.
Could this be because it's an old cpu ? (pre SSE instructions) ?

Any other reason it hangs?
TIA for any info.

 

I just tested it on an old XP2000+ cpu w/ Win2k SP4 and experience the same problem once the scanning starts. It shows the animated scanning... but hangs @ 0%. I can click cancel, it asks if I want to cancel, I click Yes and it goes back to the scanning screen and locks FF up. I do not have a s/w firewall installed, but I do have SAV Corp 10.1 & Prevx running.

Eset & F-Secure online scans work fine.