In reply to AquaticIce: You should probably have posted this in tech help, rather than here, as you would have gotten help quicker.
How to set up The Sims Medieval for Mods
1) Enable "testingcheatsenabled" in C:\Program files\Electronic Arts\The Sims Medieval\GameData\Shared\NonPackaged\Ini
2) Right click "Commands" and click Properties. Tick off "Read only" if it isn't already and click accept.
3) Now go back to the list in Ini and right click on "Commands" , open it using NotePad and you'll see "testingcheatsenabled=0". Change "0" to "1" and save.
Open the sims medieval install folder which can be found here:
C:\Program Files\Electronic Arts\The Sims Medieval
If you see folders called 'Caches, Game, Game Data, Support and Thumbnails, you’re in the right place.
Put the 'Resource.cfg' file in here, at this level, so it’s sitting with these folders.
Make a new folder called Mods.
Make a new folder called Packages. Put the Packages folder inside of the Mods folder.
Open the Packages folder and put your package files for the mods you want to use in here. This is where you would also put Grim's Core, should you decide to use it.
This is what it should look like: C:\Program Files\Electronic Arts\The Sims Medieval\Mods\Packages
Now, go back out of the mods folder (you should be back in the folder that contains the Caches, Game, Game Data, Support and Thumbnails folders and your new resource.cfg)
Open the 'Game' folder
Open the 'Bin' folder
Put the 'd3dx9_31.dll', which you can get from here:
http://www.modthesims.info/showthread.php?t=438344 , in the bin folder.
Here is what it should look like: C:\Program Files\Electronic Arts\The Sims Medieval\Game\Bin
You're all done.
Close the folders and run the game to check it all works. If it still doesn't work, please post pictures of your set up so we can look at it and see what's going on. Good luck.