Welcome to eDonkey!
Ok, the first thing I would check is your ID number.
Is like 9 -10 digits?
If it's lower then that, your router probably is the issue if you haven't forwarded the ports.
Some servers will disconnect you if you have a low ID.
Second thing I would check is any/all firewalls. Make sure you've told your firewalls it's ok for eDonkey to do it's thing.
Third thing I would check is your Max Connections.
I think the default in eDonkey is a measly 45. If you aren't on Windows 98 (98 has issues with too many more connections then say 200 or so) go ahead and raise that to like 4500 (max is 5000)
And remember to keep your server list updated.