I've noticed that when I leave Gnotella 0.73 running unattended for more than 5 hours: the number of packets being sent, recieved and dropped (for all connections) drops to zero and then the buffer starts filling up. If I close down Gnotella and then reload it, it seems to function normally. I'm not sure if it's my software or my ISP.

I've got the same problem, although I've so far only noticed when I download really big files (more than 100 mb). I have to exit and restart Gnotella over and over again, since it stops downloading the file of some reason, but resumes as it should when restarted.