There was a change this past week which would have forced HTTP mode. 2011/2012 work a little differently in this regard, but Reviver 2.3.5 does try and work around this problem a bit for 2008 and 2009 clients by changing the initial server you connect to. If either of you are interested in going back to 2009, please try the latest version of Reviver and see if it makes a difference.
Also if you have any interest and the problem is still there, a connection log of the 2009 failed connection attempt would be helpful.