My advice to anyone about to install the forums module is DON'T. It's badly thought out. It seems to have been released without proper testing. Prior to 4.5.3 it had glaring bugs. I've have endless, endless trouble with it and so have many others. Upgrading to 4.5.3 has only made things worse. The files don't upgrade the site properly. Error replacing the forums dll. Errors with the resource files. Manual fixes abound. Run this... hack that... Can't delete posts. Restart the app and access to web.config denied. I wish wish wish I had not used this module. Time and effort down the drain.

It does sound like you have an error in there somewhere which isn't standard.

What I've now been doing is updating a copy of the same DNN instance which I also use for development and testing with this first. If there's an error then I try to find out the cause but I don't touch the live instance unless I am confident in the update and of course made a backup first.  Any updates that break it and I'm restoring the backup immediately.

As for the forum module... it's had it's problems in the past and taken plenty of time to get bugs fixed but the latest version is definitely an improvement.  Updated 2 DNN instances with this and the only real problem has come down to changes in the themes which my own theme (ever so slightly modified default theme) needed.

RobWozza, I am sorry you have had issues but the ones you are explaining don't even seem to be forum related. The fact your system couldn't update the dll tells me there is other issues (also, never heard anyone register a bug with updating resource files). For the record, the module has always followed DNN standards for module releases (in fact, it did so before many of them even existed as it was the first core module released as a project).