Look SAMP got more programmers and they has more experience,so they got more players then MTA.Lua is new language and there is no a lot of programmers of Lua,and they don't has much experience.So thats why MTA have less players then SAMP
For the votemanager disable go to MTA DM\server\mods\deathmatch directory then open mtaserver.conf file go down and delete votemanager line.For other question I think you need to asking help from Scripting topic.