Multiple instances shouldn't conflict with each other in any way, and that note about memory usage sound completely fine.
I'm stumped as to what could have been causing your issue. Can I blame the antivirus?
I don't think so,I use Microsoft Security Essentials,pretty solid AV,plays well with everything.
And I've now been running it with v1.1.26.01(x32 Unicode) and no issues. Needless to say I no longer believe it's the script, I think it's something to do the combination of the 1.1.29.01(x32 Unicode) update and my OS(Win 7 x64 ultimate SP1).
I'm gonna hold off on a bug report to lexikos though, given I seem to be the only one whose observed and noted this issue on the forum. Cheers & Thanks for looking into it.
Outsourcing Clicks & Presses Since 2004.