Well i seem to have a problem with this mediavps folder. I created that folder, put my MV_*.* files in there yet they dont work when i load up he game. They do however work when they are in FS2's root folder. I believe i am using the official 3.6.7 build.
Did you go to the mod tab in the launcher and select your mediavps folder as your mod? The media VPs won't automatically work from the media VPs folder. You have to run them as if they were a mod. The advantage of doing things this way is better compatibility and also you can turn them off with a few mouse clicks to check whether they are the source of a crash or not.
Also hopefully you look but a quick question about compatibility. Would a current CVS Fred mission not work with an old version of FS2_Open?
Depends on how much older. You could probably get away with a couple of weeks difference depending on what has been added in the meanwhile and whether or not you are using it. In general it is a bad idea to do this especially when there is a large gap. CVS FRED builds from pretty much any time this year make missions that are guaranteed tobreak 3.6.7.
Also would an older version of fred missions not work with newer FS2_open?
This is a lot safer. There are a few little problems (ai-chase-any-except has been removed for instance) which can cause you problems but there is a reasonably good chance that FRED missions from fairly old builds will open in modern FS2_Open.
Also saving the file in a newer fred and opening it in an older fred doesnt work, that is expected to happen correct?
Yep. That probably isn't going to work for the same reason opening it in FS2. In fact both are parsing the mission through the same code so if CVS from one date won't open in FRED it almost certainly won't open in the corresponding CVS build of FS2_Open.
The general rule of thumb to follow is always try to use a build of FRED which is older or the same age as the build of FS2. The same age means that they are more likely to be compatible but also means that they may suffer from the same bugs.