Indeed, I've disabled ultrapeer capabilities. But that's not the problem; the problem is that it's impossible for me to sustain a bandwith of 16 Kbyte/sec. If I upload something bigger than 3 megabyte, my connection will terminate.

And if anyone with the same provider uses limewire, the program eventually will become an ultrapeer (happened to me also), and the connection will become unstable. The person using limewire will think 'hey, this program makes my connection unstable', and stop using limewire.