Logon, su to ldm (sudo su - ldm) and run:

ldmadmin start

If the queue is corrupt, the LDM will freak.  In this case,
do the following:

ldmadmin stop
ldmadmin delqueue
ldmadmin mkqueue
ldmadmin start

It's good to run: ldmadmin watch after that, just to verify that stuff is coming in.