Turn off all unneccessary services like firewall and antivirus. I have now a dedicated pc for the software, a sempron 1700 with only a gig of ram (not connected to the net at all) and it runs fine without this problem now. I think it could be a reserved memory issue.
I was also experiencing this, now have a dedicated PC for the software with only a gig of ram on a sempron 1700 and NO other services running like antivirus or firewall.
Trouble is now Zulu won't scan WMAs to play them! oh well....