iPhoto '09 Library Thumbnail's Broken

Hi, some weeks ago -I don't remember exactly when- all my iPhoto thumbnail's disappeared. I have tried both automatic (command+option at startup or something similar) and manual (deleting some associated files from the library folder, forcing iPhoto to reconstruct). Both methods give me a little progress bar, that takes about 1 min to complete, which seems absurd seeing that I have +7500 photos. I could just copy the files out, and start from scratch, but I would lose faces and GPS etc. The photos are fine, when I open one it loads without a delay & with full quality, and permits me to work normally.
System Specs:
Nombre del modelo: iMac
Identificador del modelo: iMac4,1
Nombre del procesador: Intel Core Duo
Velocidad del procesador: 1,83 GHz
Memoria: 1,5 GB
Versión del sistema: Mac OS X 10.6 (10A432)
Versión del kernel: Darwin 10.0.0
iPhoto Setup:
On an external HDD, mounted at /Volumes/Media. Is ~20GB.
I hope you can associate the spanish phrases with the correct english ones, since I don't feel like switching langs.
Note: I'm about to run the 10.6.1 update, so I'll be running that.

Sometimes I really feel like I'm about to leave the forums, no one ever responds to my threads. I guess maybe it's my problem, if I'm doing something wrong just let me know, anything is better than eternal silence:
"La indiferencia es un hielo, un hielo que, mientras lo momifica, le perdona la vida, se la perdona nada más que para eso, para que usted se sienta momia, se sepa momia, en el frío y en la oscuridad de un sarcófago." Marco Denevi, Rosaura a las 10.
It's a very good book actually, I recommend it to anyone. I don't know how goot is is in english, but it can't be that bad.

Bump.

Used iPhoto Library Manager (or what ever it was called) to re-import all my photos, and now have everything ok, except I lost about a dozen pictures.