Thank you! I will have to look into this in more detail later today.
I may need to send you a development version in order to capture some
details about why twitter is sending back that error. If you haven't
reached your rate limit, then the only other reason for getting that
error is if twitter is receiving a request from Trowl that it doesn't
understand. Off the top of my head, the only reason I can think this
is happening is if you have a firewall or other web filtering software
that is intercepting the call. You already said you created a
firewall exception for Trowl, so it may not be that either.
I'll look into it and let you know. Thank you for reporting this!