I am also having the same issue with the email trigger.
Even when recreating the trigger, and even the job, it fails with the same error as soon as it is triggered, and sometimes restarts the VC server.  The original trigger did work, for a period of time, and now cannot get it to work again, even after recreating the trigger and even the job.
2/23/2011 11:51:17 AM	Debug	Retrieved mail: UID= 2677769
2/23/2011 11:51:17 AM	Debug	oClient.GetMail
2/23/2011 11:51:25 AM	Err	An unhandled error has occured (please send the information below to 
support@visualcron.com): 
Server version: 5.6.9.17918 - (2009-09-21)
Protocol: 5.6.2
OS: Windows2003
System.NullReferenceException: Object reference not set to an instance of an object.
   at VisualCronService.InternalEventsAPI.GFNKIBIJCFAPNOABNGLEKHINPKDOJLEMKMKN(JobClass , TriggerClass , ConnectionClass , String )
   at OBOKIIHBDBPMCFALPGECCIFHCDJPEDKODDGK.KEMLEDMDNELBHFFOFDEDHAAKAHOPFGNIJMEI.MCJFOMFKCEOBMBPKDAOADFMPPKNLHIJFCJDG(Object )
   at System.Threading._TimerCallback.TimerCallback_Context(Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading._TimerCallback.PerformTimerCallback(Object state)
2/23/2011 11:51:25 AM	Err	An unhandled error has occured (please send the information below to 
support@visualcron.com): 
Server version: 5.6.9.17918 - (2009-09-21)
Protocol: 5.6.2
OS: Windows2003
System.NullReferenceException: Object reference not set to an instance of an object.
   at VisualCronService.InternalEventsAPI.GFNKIBIJCFAPNOABNGLEKHINPKDOJLEMKMKN(JobClass , TriggerClass , ConnectionClass , String )
   at OBOKIIHBDBPMCFALPGECCIFHCDJPEDKODDGK.KEMLEDMDNELBHFFOFDEDHAAKAHOPFGNIJMEI.MCJFOMFKCEOBMBPKDAOADFMPPKNLHIJFCJDG(Object )
   at System.Threading._TimerCallback.TimerCallback_Context(Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading._TimerCallback.PerformTimerCallback(Object state)
2/23/2011 11:51:25 AM	Err	An unhandled error has occured (please send the information below to 
support@visualcron.com): 
Server version: 5.6.9.17918 - (2009-09-21)
Protocol: 5.6.2
OS: Windows2003
System.NullReferenceException: Object reference not set to an instance of an object.
   at VisualCronService.InternalEventsAPI.GFNKIBIJCFAPNOABNGLEKHINPKDOJLEMKMKN(JobClass , TriggerClass , ConnectionClass , String )
   at OBOKIIHBDBPMCFALPGECCIFHCDJPEDKODDGK.KEMLEDMDNELBHFFOFDEDHAAKAHOPFGNIJMEI.MCJFOMFKCEOBMBPKDAOADFMPPKNLHIJFCJDG(Object )
   at System.Threading._TimerCallback.TimerCallback_Context(Object state)
   at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading._TimerCallback.PerformTimerCallback(Object state)