To be more specific when Detect shellcode injections -setting is enabled PowerDVD 8 Ultra fails to start at first time you try to execute it. Setting it to exclusions list in image execution control settings seems to fix it. When this buffer overflow protection is enabled PowerDVD crashes when trying to play content. Also for some reason when that setting is enabled PowerDVD fails to detect video card and audio controller thus making it completely unusable.
OS: Vista x64, AV part and firewall part are enabled too.
I’ve got exact same problem with PowerDVD 9.
I think that this might be a real problem for those who don’t know what’s causing the problem and for some beginner users.
Yet another reason to disable Image execution. if you have installed the AV part of CIS,Image execution ,in my opinion, is not needed.
Yeah, it gives more trouble than it’s worth keeping. Also, thanks to packer detection CAV gives plehtora of flase positives when installing PowerDVD - and that’s just an example, packer false positive is really common from CAV.
Wow thank you guys!
This was the final hint so I could use my flash tools again which were:
SWF Encrypt, Riva FLV Encoder, Riva FLV Player, Eltima Flash Optimizer
They all crashed immediately and the only thing I figured out was that they were working in safe mode. Even when I disabled Defence+, they crashed so I didn’t think of CIS.
One of the biggest differences between running it in safe mode and “full mode” was, that always the “cmdGuard” minifilter was loaded.
I considered going back to the latest backup, un-installing Vista SP2 and MUCH more.
Finally this thread led me to the right thing to do!
I just unchecked the box that controls shell code injection/buffer overflow protection and whoopie, they all run again.
Glad you found out what was causing the problem.
You can add Exclusions for Detect shellcode injections so you do not lose all buffer overflow protection.
Dennis
Unfortunately, the latest comodo Update re-introduced Crashing for the applications above 
It seems I have to turn off defense+ completely now If I want to use any of those programs further (well I payed money for them so this will be the only way…)
Edit: Oookay, I found that the update re-enabled that switch mentioned above. I had to find it again and now I set those programs as Exceptions instead of completely disabling it.