MRP 3.3.54 (the latest version) is designed for World of Warcraft 3.3.3.11723.
If you’re on a test/alpha/beta realm, or are running WoW 3.3.5, you need compatible addons for that version, as many incompatible changes have been made.
However as the final patch 3.3.5 is
subject to a rolling release due to the RealID feature, and I’m in the EU, I’m afraid you’re out of luck for this addon at least a week.
MRP4 is in early development and is a substantial rewrite. I plan for it to implement the channel-free ‘Mary Sue Protocol’ (which is for the moment still in development, but a little further on I hope to invite and get other RP mod authors like TotalRP, FlagRSP2 and ImmersionRP, and also of course possibly MarySue, on board for a possible change to migrate away from the legacy xtensionxtooltip2 method), having now measured for certain that that
is more efficient on both your CPU and bandwidth, and the server’s CPU and bandwidth, on test and live servers, especially on heavily-loaded live servers with a busy xtensionxtooltip2 channel.