Have you solved the problem yet?
For me and this other fellow the problem was a windows update.
Ever since I installed the windows update KB841356, windows no longer likes something PJ64 does and gives the failed to allocate memory error on my pc.
It is for me as simple as this, I put the windows update KB841356 on and PJ64 does not work, I take KB841356 off and PJ64 works.
Which is not very nice since I don't really like to recommend removing a fix to a known security issue in windows. I would at least recommend that you make sure that you give your firewall and virus scanner a good checkup before you remove the update (that is if you have the update) as it will mean having not as secure a system and relying more upon your firewall and virus checker to do the job.
The original forum entry is here
http://www.emutalk.net/showthread.php?t=24586
Nick