If you have a completely up-to-date OS installation including fully up-to-date and working installations of .NET and IE7 Impulse should be working like a dream.
I've got it running on computers running XP (32), XP (64), Vista (32) and Vista (64)...none of which have had even one single issue with Impulse.
How about some OS info along with patch-levels of the OS etc. and we can try to troubleshoot this for you....
thanks,
the Monk