Session ids blocking themselves

theres a scenario where in a session id is blocking itself. the wait type is latch_ex - access_method_database_parent

I am capturing the queries and will work on optimizing them however am looking for possible reasons for this.

Environment

Windows server 2008 sp2, SQL Server 2008 R2 ent sp1, CPU=32 , RAM 32

Server level MAXDOP=0 tried changing it to 16 but the problem persists.

Thanks, Ahmad Osama www.ahmadosama.net http://www.sqlservergeeks.com/people/AhmadOsama