FYI - The changes made with the new multiplayer and Pitboss functions for Civilization 5 will break previous save games and mods.
Started a new vanilla game after the patch, the issues did not appear (spinning globe cursor, hangup on diplomacy screen).
Looks like a quick fix is already available: http://forums.civfanatics.com/showthread.php?p=12568296 (http://forums.civfanatics.com/showthread.php?p=12568296)