I noticed this in the last two times when i started the game, the updates were extremely slow. In the last 15 minutes only 7% of the update was downloaded. Is there a problem with the server?
On the other hand, i have an adsl router. Should i do some port mapping in it?

I have a theory on this!
Maybe, somehow, your media.rlb got corrupted, causing it to re-download the whole thing?

Nope. It took around 6 hours to download 2.5 mb (approximately) for the update. In the meanwhile i downloaded other things, and some downloads reached extreme speeds while this one was the slowest i ever had. It might be a routing problem, since my ISP is not the best of the best, but i never experience lag when I play. Only when i update the game. (and since i'm pretty new, i had only two updates till now. first one was 20-ish minutes, and this one was extreme).

hmm, odd . No idea really , since updates normally take a couple of minutes ....

Maybe your other downloads at maximum speed ate your badwidth?
I know it happens to me if I am simultaneously sending a mail with a big attachement and downloading something else.
Try VO update as the only download active. That will prolly solve your problem.

P.S. constant & massive pron torrents/downloads will seriously damage your brain. :P