I have also seen this error. However, after about 30 seconds the client went ahead and processed the push operation. In my case I was attempting to restart the remote endpoint. Another anomaly I noticed was the push job I created had 1 machine selected. The push job shown in Push Operations contained 2 machines, the machine I selected plus a machine that had previously been in the asset list. Once the job completed and I cleaned Push Operations (delete). When I went back to Asset Management the 'plus machine' had disappeared from the asset list. I ran the job a second time and the same anomaly did NOT occur. It is my feeling that the DA problem is related to a database inconsistency, possibly with deleted objects.