0.9.1 reply / new topic page error

reply / new topic page error

when i enter reply or new topic the link jumps out of joomla template to white page and you cannot enter anything.

has anyone come across this error or has a fix for it?
I am become frustrated and desperate now, I have installed and uninstalled many times and get the same error.

I would really like to use JooBB as I like simple interface but I am really tempted to go SMF now.