lost album.dat - lost 50k of photo's and hundreds of albums - help

Hello

I have a little problem on the website /gallery which i have put together for a friend, it has 58k photo's on it and he sells his photo's from the website.

if you look at the gallery at www.a-w-p.com/gallery2 you will see a list of categories, the top and most used one is sport which should contain 50k of the 58k photos or around that mark,

about a week ago the site came up with invalid albums for 'sport' and 'album616' - i got a phone call to tell me this as i was working away i asked my brother to move the album616 and sport out, then move sport back in.
having done this it only came up with invalid sport albums, looking inside the albums (which contains no photos) all of the files with empty apart from the thumnail file,

now the problem i have it i have a backup from about 4 months ago which i have put in and some of the albums have come back inside sport.

but for example album332 which is rugby union should be inside sport, but it is not there anymore, i can go through all 630 albums on the site and work out which should be inside sport but i have no idea how to get them to show in sport.

i guess it is something to do with the 'album.dat' files and other such files located inside the 'sport' album directory.

so my question is how can i change the album.dat file or the file i need to edit to get it to show the albums which should be inside the sport directory?

The following information is required to get an answer:
Get this information from the PHP diagnostic (in the configuration wizard).
Gallery URL (optional but very useful):www.a-w-p.com/gallery2
Gallery version:1.4.4-pl4
Apache version:
PHP version (don't just say PHP 4, please):PHP v4.3.11
Graphics Toolkit:ImageMagick
Operating system:Redhat
Web browser/version (if applicable): N/A