The following links discuss this database error:
One thing to try is to change the Max Degree of Parallelism in the SQL Servers Advanced Settings. SQL makes a parallel query plan at optimization time. Maybe not all of the processors were available or there were not enough threads available. Try setting MAXDOP to 2 or 3 to see if it helps. This can be done on Enterprise manager by right-clicking your server and go to the Properties item "MAX Degree of Parallelism."