Sounds to me like your internet/computer just is too slow so the bot starts trying to forward packets before the connection is established (happens if you have ANY lag at all).
IE: my laptop earlier on a random wireless network took me like 30 tries to log in... my desktop logs in first try every time (RARELY I have to try twice) but it's a quad core i7 proc, 8 gig ram, etc, wired connection, etc.
Ideally you'd need to check that the connection is established and 'ready' before sending packets either way (generally forwarding to server before the connection is established is the issue here) or it taking long enough that the proxy tries to send it's welcome msg or w/e.