In some cases, you can get an error 0x00000005 (Access Violation) in the SQL Server process, that is caused by running external COM objects via sp_OAcreate. The effect is that the entire SQL server process rolls over and dies immedeately.
This can be quite hard to solve without the help of Microsoft PSS, but there is one thing you can try that might help. When you call sp_OAcreate, use option 4, wich will spawn teh COM object in a process outside the SQL server process. If and when that process crashes, atleast it will not take down the entire SQL Server process with it.
Read more about sp_OAcreate at http://msdn.microsoft.com/en-us/library/ms189763(v=sql.105).aspx