I love vanilla - it's clean, well designed and thought out and standards compliant. I love the way that discussions are laid out in a similar style to basecamp as well.
Only issue is that Ive done a fresh install but I get these errors at the top of each page:
Warning: Undefined property: Connection in forum/library/Framework/Framework.Class.MySQL.php on line 53 Warning: Undefined property: User in forum/library/Framework/Framework.Class.SqlBuilder.php on line 309 Warning: Undefined property: Scripts in forum/library/Framework/Framework.Control.Head.php on line 22 forum/library/Framework/Framework.Control.Head.php on line 31 Warning: Undefined property: Strings in forum/library/Framework/Framework.Control.Head.php on line 40
I don't think it has anything to do with your PHP version. If the errors change when you re-upload the files, then it sounds like the files are getting garbled by the upload somehow.