I'm leaning more towards Reinstalling the the SymSnap service. I've had to do this a couple of times when using version 8.0
http://seer.entsupport.symantec.com/docs/305260.htm
http://seer.entsupport.symantec.com/docs/303346.htm
http://seer.entsupport.symantec.com/docs/306769.htm
http://seer.entsupport.symantec.com/docs/303972.htm
Also, Have you tried assining a different and/or shorter name, i.e. Ext-Drv