You have lot more locks than the server can handle.
Start SQL Query Analyzer, run a query that gives you the list of processes locking each other and kill the one causing grief.
A sample query is as follows:
USE MASTER
GO
SELECT * FROM SYSPROCESSES WHERE SPID IN
(SELECT SPID FROM SYSLOCKS) ORDER BY BLOCKED DESC, SPID
and use:
KILL <SPID>
to kill the process blocking others.