The same situation is happening with my setup (client<=>server) after the upgrade. I'm using 1.6 pre-release already.
So, I followed the advice and disabled HTPC Info. After that, the problem was solved and MEPO loaded much faster. I believe this problem is related to the TV connection timeout and something within the HTPC Info plugin.
in the Plugins section of MP Config on the client. go to HTPC Info and press the config button for Setup, On the first tab (Monitoring), and about halfway down the list is Monitor TV Server... just uncheck that.
The client side requires some TV Server dlls to be added to the MP folder on the client for the TV Server Monitor to function... it's in the docs for the HTPC Info plugin, I just didn't set it up. At least that's what I understand.