I have just compiled the brand new 2.2.2 and the breaking network bug is still here.

As others described, the issue is that, when ktorrent is on, it breaks the other connections to the Internet while ktorrent is working fine!

I'm desperate , if it is not ktorrent, where does this bloody bug come from?!

Isn't that related to router mishandling excessive UDP (DHT) connections?

If you mean many when you write excessive, i've alreday lowered the number of max connections but it didn't change a thing.
I feel the ping for the other connections are lowered to the lowest priority but I may be wrong.

Any other idea?

Did you try disabling DHT and seeing how it works?