Thanks for those. They show the service blocking on startup of the groups, and in particular the groups blocking on RSLinx. The interesting part is that it’s blocked in a slightly different location each time, once on adding items to the subscription, and once when simply pausing the subscription, which it does right before it adds the items.
Just out of curiosity, if you go into RSLinx>DDE/OPC>Communication Events, are there many errors? In looking around, I’ve found a number of reports like this one that show that an overflow in error messages can cause OPC problems with Linx. Now, it seems like it’s happening a bit too quickly in your case to be this, but who knows.
Just out of curiosity, have you tried connecting directly through our AB driver? I know it might be a pain to change all of the item paths (though with the group XML export, you could probably search and replace, I think the core address structure is very similar), but even if we got through this particular problem, you may just hit a different problem in the future. RSLinx is notoriously bad as an opc server.