I just had a hellish week repairing MOSS 2007. Details will follow when I have completely recuperated from the ordeal. However, I thought I'd post a little problem that I encountered with MOSS 2007 that seems to be a common bug. At first, I didn't think it was little, actually I was "sweating bullets" when I saw it because I had just successfully brought back MOSS 2007 after it was completely down. So seeing this error didn't help. In any case I saw this error message, "The trial period for this product has expired" when I was editing the master page of a SharePoint site. It would not let me check it back in, or publish it (I am running MOSS 2007 Enterprise).
So I did a bit of searching across the net and didn't have problems finding information on it in terms of people talking about it. It seems to be a problem quite a few users were facing. And what makes it even harder to diagnose is that there are multiple reasons for this error. If MOSS 2007 is installed on a DC for example, then a different fix will need to be applied. For my situation that fix did not apply because I have two-machine setup so far. One being the web front end and the other being the SQL database.
To cut a long story short, I did a repair on the MOSS 2007 web front end because I was out of options as the time it was down. So I tried many things, repair being one of them. Now apparently if you do a repair, it seems to only try and fix any damaged or corrupted files but does nothing to the registry (I'm assuming). I had to run the configuration wizard in order to fix the error for "The trial period for this product has expired". The configuration wizard basically updated the registry and all settings that seemed to have been lost during the repair. So while I am still unsure of exactly what caused it, this is my guess.
So, if you encounter this error AFTER a repair of MOSS 2007, remember to run the configuration wizard right away with all the default settings.