The beta version didn't appear when I typed /proximo test (I tried several times). I can only assume that it's somewhere offscreen due to the new scaling system.
My modified target scripts look quite different:
button:SetAttribute(type, "/target "..name.."\n/script DEFAULT_CHAT_FRAME:AddMessage('Targeting "..name.."')")
elseif option == "focus" then
button:SetAttribute(type, "/target "..name.."\n/focus\n/targetlasttarget")
elseif option == "spell" and spell and spell ~= "" then
button:SetAttribute(type, "/target "..name.."\n/cast "..spell)
The  is essentially a no-op, but somehow it works around a bug in the macro system. Someone on the EU mage forum posted the tip, IIRC. I'm pretty sure I tried [target=name] style targeting too and didn't get it to work, but maybe it would have also needed an extra . My other macros work fine without any tricks like that.
I got the proximo frame back by resetting my profile and reloading the game. Now I have a new problem. I was doing arena yesterday and sometimes the frame would not work(/proximo test would show the frame in the correct spot). Sometimes it would be loaded _OUTSIDE_ of the arena. I found a way to fix it for the _next_ game by typing "/proximo enable" followed by another "/proximo enable". It wouldn't work for the current game, but the next arena game I used that command it would load up like normal. It still loads up outside of arena now.
I've switched back to an old version of proximo while this gets fixed, I rely heavily on this mod for targeting in arena!.
Did about 20 arena games today and 3-4 times proximo did not show up while inside the arena. It then became visible when zoning out. I remember it was in ruins of lordaeron, not sure if the problem is limited to that zone.
Nice work so far, totally replaced Gladiator for me. One minor request tho, on the low health announcement, is it possible to add a class tag in there as well? For some of my teammates with no arena frame mods (even those that do...), throwing a name out there sometimes doesn't help since we don't remember our opponents names, but if you call out a class they know immediately who you're talking about. The name should almost be secondary in case there is more than one of a class.