Thanks for this - I was having a very similar problem with Producer 6, and Parallels 10.1.1 running on OSx 10.9.5
I upgraded Proshow from 5 to 6.0.3397, and everything fell apart. Clicking a menu caused the program to close. Trying to create a video Proshow said the program was unlicensed. I'vealso used
http://www.proshowenthusiasts.com/viewtopic.php?f=2&t=22652&p=170639 to change my Windows 8 VM settings. Though I must admit I'm still only using 4 of the 8 cores on my Mac - it's enough for ProShow and it's also not the only Windows program I use. My Business accounting software is run under windows and when I use that I need to be able to use the mac at the same time.
Not tried quicktime rendering yet - that's for another day
Completely uninstalling, rebooting, then reinstalling the latest versions seems to have solved the problems - so far.....