I presume you don't have a recent-enough catalog backup (?)
I bet you won't let that happen again..
Anyway, depending on what's wrong with the catalog, you may be able to recover develop settings (only) via a plugin called WreckHover (free, by me).
In addition to catalog, settings may be stored in:
* xmp if you've saved metadata (if not, I bet you won't let that happen again either) - recovered when importing new photos, or reading metadata (Library menu) of already-imported photos.
* exported versions (if exported with all metadata) - you can recover settings from those via the same plugin: WreckHover.
Note: you'll need to restore a backup catalog first, or start a new one if no backups (really?).
may be this article can help you: Mein Lightroom Tag: Einen Katalog reparieren, welchen Lightroom nicht mehr öffnen kann!
Basic idea is to make a sql dump and re-import this dump in an new catalog. (Don't forget to make backups before)
Thanks for the advice. I tried using the plug-in, but I'm not sure if the catalog is too corrupted or something. When I do part 1, I get a warning which states, "WARNING #6: sql query error: Non-zero exit code returned by command" and then the path name for the plugin, then the path for the source file and the fields from the source file you are querying and then it says, "exit code: 2816."
Any idea what this means?
Thanks again for the help!
Hmm - not sure what that means Andy, but it may mean that sqlite can't read the develop settings table.
As you said, it could be that the catalog file is too far gone.
Have you tried opening it with an sqlite app, like SQLiteSpy (Windows). If it can be opened, then there is a chance at recovery. If not, it doesn't bode well.. - you could also try the article posted by THG_BO, if you speak German.
Anyway, sometimes Adobe personnel will help with corrupt catalogs, if you can get their attention.
Not sure what else to say..