What are some good tips and tools to use when fixing PHPBB DB corruption?

Good evening!

I run a moderately large, PHPBB forum, which has various (for the time being) non-fatal amount of data corruption. for example, I started noticing what appear to be PHPBB "names" substituted in places they should not be, such as menu fields and in content.

Here is what part of my ACP menu looks like:

You are logged in as:
[ Logout ][ ACP Logout ]     

QUICK ACCESS
Manage users
Manage groups
Manage forums
[...]
Avatar settings
Private message settings
Post settings
Signature settings
ACP_FEED_SETTINGS   <--- WTF?
User registration 开发者_C百科settings
Visual confirmation settings

I would like to, very soon, attempt to fix this by hand. My plan is to:

1. take the board offline
2. make a backup
3. dump the data to file
4. identify the problem
5. fix said problem, possibly including verifying the install
6. test solution

My hunch is that one of the many updates over the years didn't work exactly as planned (I upgraded from version 2.x-something). The forum is a vanilla install.

I am asking this question because I don't have much experience with SQL (strangely enough). I know several programming languages (perl is my best), but just left the database stuff up to other people.

As I have never attempted this before, I would love thoughts on how to identify the corruption, tips, general advice, common pitfalls, etc. My searches have not revealed much useful advice, so I turn here, to SO!

Thanks in advance!