Im Laxsod and if anybody got a message about a new version of MTA:GTA3 which it said version 0.5.1 its also said that do not report error messages cause there doing the new version so i dont know if it wrong to post this so i did.
And the way i got it is to play MTA or start the game dont click on start multitheftauto just click on Load game choose on one of your games and the message will come up.
Because it "supposed" to be like that. You cant load saves, because mta is using diffrent scm. file. (the same like in singleplayer when u change scm. and load saves game will crashed). Thats why you getting error messages.
The other way to get error its changeing game options in MTA(eg. resolution)