Wdhd hub media center issue with to many avis?

Im having a problem with my wd. it seems when i put more then 400 videos on ( they are all avis), it takes about 250 of them out of my video list. They are still on the wd. I can see them with my computer just not with the wd. Then I remove a few of them, and the rest come back to my video list. Not the end of the world, but very annoying when you have a lot of tv shows. I thought i might be running out of space but this is happening and theres less then 500 gigs on it so i dont think thats the issue. Anyone have any ideas?

Do you have all of them in one folder? 

Yes, they are all in one folder. I was thinking (havent tried yet) could it be that when .avi’s are added it starts re-scanning from the begining and i havent given it enough time to scan them all again. Maybe