I can't view Youtube videos on my BB! It says "An error has occured attempting to play media."

Also, sometimes when i try to open Internet pages.. it just says Requesting, but loads really slow, then nothing happens.

Are you going to:
h t t p : / / m . y o u t u b e . c o m ??

No, i use w w w.youtube.com

Just for fun i tried m.youtube.com

It works, tried to load a video, says "Content not available. Server is blocked or unresponsive."

Pull your battery.

Tried that.. no luck.

Are you on BES or BIS?

Could you tell me what that is? How can i check?

BES = getting the service through your company and they can "manage" your phone
BIS = straight through your carrier.