Ok for some reason my server doesn't save my player data and I'm scared that this may start to happen to other players and that they'll abuse this. This happens only when I'm in gamemode 0 and when I open a enderchest I get end of stream and then my position resets to where I was when I first logged in and so does my inv so any help? the error: [Server] WARNING Failed to save player data for supersean61
Seems like a crash perhaps you should check your crash reports on the root folder? someone can take a look into it.
http://pastebin.com/H5eSPMi3 This is the closest crash that happened and this was on the 12th my player data was still good at that time.
It could be the spigot build, first step though is to disable the plugins you think are causing the error, and if it persist, then it is the spigot build.
As this is Bukkit, we do not support Spigot here. You'd be best asking over on their forums rather than here.