Please give some more details of your problems.
Like give details about your setup
And other info, like:
what you might have changed before you started getting the problems?
What have you tried to fix it (and which presumably didn't help fix it)?
Have you tried any other Bittorrent clients on the same setup and did they also give these problems?
Do you have anything else using the connection when you get these problems (for example like any other 'file-sharing' apps)?
If you can give more information I hope we might solve the problem!