I'm sorry to say, and while I appreciate the work and time put here by some of you about this issue, I find these explanations rather confusing.
First, there's an initial process described, which is then aparently to be used ONLY with forums that have been hacked. How would somebody know if it was or not? Our site was aparently hacked around the time this issue arised [we found a "root" page instead of the normal index, if this was a "hacked" site as described here?] and proceeded to reinstall our site and applied a patch to the forum as instructed initially by LP. This patch didn't upgrade the forum, but just replaced a few words in the code in a certain page. Since then, we didn't have any issues with the forum or the site.
The instructions provided above [BTW, the link provided doesn't work anymore!], are refering to some files that are upgrading the 2.0.x install to 2.0.11. Since I couldn't use the link provided, I went through the phpBB site and downloaded the files for upgrading to 2.0.11.
These contain apparently more files than described in this thread, including the 2.0.x .zips for different upgrades. These .zips, when opened, have a bunch of php files that do not corespond to any directory structure as found in the forum backup!
Further, in the control panel, there's an option to upgrade to the 2.0.11 forum from the "bulletin board" link. Does anybody know if this is functional, and how to use it? When I click on the "upgrade" button it asks for a directory for the install, however there's no field provided to insert this directory. There's one under the "install" option, but that would probably install a new forum, losing the existing database.
Is there a way to do a "clean" install, just overwriting everything, install a new forum, then reinstall the current Db and mods?
Sorry about the long message and lots of questions, some of us are not programmers or very familiar with these issues.