How do I fix a corrupted database?

[Baasha <baasha shaw ca>]

I have about 200 photos in F-Spot that are inaccessible.  When I am in 
browse mode the thumbnails for these photos are visible, but when I go 
to see them full size all I get is that gray  photo slide icon.  When I 
select View>Metadata I get the message that the photo doesn't exist. 
However when I go to the directory where my photos are stored, 
everything is there.

I had a look at the database, but there are so many different sections, 
and bits of information, that I'm not sure what I can edit safely 
without making a complete mess.  What can I do to safely restore my 
photos so that F-Spot can see them?  The 200 missing pictures represent 
approximately half of my total collection.  I am running F-Spot 0.4.3.1 
on Ubuntu Linux.

Thanks,
Bob