Tried using FST4W last night on 630m for the first time with WSJT-X Ver 2.3.0 rc2.  With t/r duration greater then 300 sec program would terminate when the period started.  I disabled the watchdog timer, eliminated rig control, and even removed then reloaded the rc2 beta program without success.  Has anyone else seen this behavior?  Is this a potential bug or am I doing something wrong?  Any ideas on how to troubleshoot this.  My OS is Windows 7.