Have you disabled your vbulletin plugins and any hacks you have done like vbspell etc. All those plugins will break the comments box in vbulletin? You can send me an admin login via PM if I understand your english there and I will have a look.
I am not the developer of Photopost Pro only Reviewpost and Classifieds so I can not say what features any new features it would have. We just released 6.02 a few months ago and any new version would most likely be 6.1 when it came out.