Crashing GWIA

I am currently having issues with both our IMAP servers. Both received the same fault within 24hrs of each other. They will both work very intermittently but then also fail after 10min or so.
The only consistency is that in the event logs I get the following;

Event Viewer - I get this when it does work and then fails
Faulting application gwia.exe, version 7.0.3.1527, faulting module ntdll.dll, version 5.2.3790.4937, fault address 0x0001bb52.

Gwia log - This UDP error occurs when it doesn't work after a restart.
12:00:17 3D4 ******************* Agent Started *******************
12:00:19 3D4 HTTP server running
12:00:19 3F0 Starting GWHTTP-Listener
12:00:19 3F4 Starting GWHTTP-Handler_1
12:00:19 3D4
12:00:27 3D4 Error, Internal Udp Port is unusable. [8912]
12:00:27 3D4 Shutting down thread: GWHTTP-Listener
12:00:27 3F0 Exiting GWHTTP-Listener
12:00:29 3D4 Shutting down thread: GWHTTP-Listener
12:00:29 3D4 Shutting down thread: GWHTTP-Handler_1
12:00:29 3D4 Shutdown of Threads
12:00:29 3F4 Exiting GWHTTP-Handler_1
12:00:29 3D4 Begin Configuration Information
12:00:29 3D4 Platform= NT

Any help would be appreciated on the matter. Running on 2003SP2