Ran into this too... We have two BES's... for this discussion we'll call them Bes1 and Bes2...
We ran into this issue of "packet size greater than 64000" being sent to RIM's network 5 times in under 1 min... (Yeah, fixed in service pack)... which caused RIM to disable our SRP key for BES2 that this happend to... BES1 was up and functioning normally...
The only "error" condition we saw was the red X on the BES name, and saying Disabled in the blackberry manager software.
The SRP Connection test button on the Blackberry Router tab of the Blackberry Server Configuration program worked...
Of course it needed a call to RIM, and having them re-enable the SRP key, then explain this error to me, and help me find it in the error logs...
So now the server team and operations are trying to add netiq monitoring to my server now, and want to monitor that SRP connection...
Applying Service pack 5A and hot fixes later today to both servers to help prevent in the future...
But now I have to try and SIMULATE this failure so they can test the script... but I have no clue how.