Just curious - have you talked to your VAR regarding this problem? It would be good to hear their suggestions.
Check in the license manager on the clients and make sure the License Order is what you expect.
If SolidWorks sees on license and can't get it, sometimes it stops and doesn't try anything else.
In the past I have had issues where SolidWorks would pull the Simulation license from Professional or Premium and then wouldn't give all the functionality. Had to put Simulation first. I don't know exactly how SWPDM Standard licenses show up in the list, so I might be off.