After installing your hack I now only get a white page when I click on one of my forums. Now what? I found the instructions hard to follow as well. Please make upgrade instructions more simple. I mean do I copy over files or just run the upgrade php (which I get errors on) or both?
Can you go to general settings and switch on php debug and then post the results here?
To install you overwrite your newbb files and run the upgrade script. Then you go to system/admin modules and click on the "update" icon to the right of the newbb module.
It is safer when overwriting files to first rename your old newbb folder on your server to something else, and then upload the new one, this provides you with a backup copy if anything goes wrong.
If you are getting errors the phpdebug should help to trace the source