Why did you check the licence.txt at the startup of the program?

And why does uniuploader send so many traffic between the host and wowroster.net.

Can i stop this?

You don't own a copy of UniUploader. License.txt is your agreement with the owner that allows you to use the program for free.

And the traffic to wowroster.net, I would guess, is checking for any UniUploader program updates... Try unchecking the "Check for new versions of UniUploader on startup" box and see if that helps.

And you could ask Matt's permission to create your own copy of UniUploader which removes these features using the Source Code posted in the downloads section if you're really that worried about it.