Let me describe the problem we are having at http://stampingfriends.com
This is the latest version of photopost on top of vbulletin 3.5.4. I have uploaded as admin, as well as my wife has uploaded as a regular user multiple times. Now it seems that some of the users cannot upload.
They upload ok, then they end up getting an error 500 message and it doesnt go all the way through. If I look into their upload folder on the server, the file is sitting in there. This seems to be happening to some people, but not others. they are all stadard registered users besides myself.
I am using GD2. Upload and subfolders are 777, as well as data and subfolders. File uploading is on, as well as set in php.ini. Max upload size is 20M which is more than enough for the files that have been attempted. There is no maximum upload limit for users.