I'm afraid I don't have any answers to this question; I am experincing the same error myself.  I wonder if this problem is related to the other problem I am having on my SQL Server at the moment (http://www.experts-exchange.com/Databases/Microsoft_SQL_Server/Q_20946416.html)

You suspect your problem is related to CDOSYS, whereas I suspect my problem is related to ADO. To fix my problem, I need to stop and restart my SQL Server services, then it all works ok for a few days. Does this work for you also?