Are you on the .exe or .swf version? If swf, are you running it via a browser (which?) or through the flash player projector?
As mentioned in the FAQ, the folder should be the same as Kong except replace "chat.kongregate.com" with "localhost".
On Win7 for example the path is:
C:\Users\User\AppData\Roaming\Macromedia\Flash Player\#SharedObjects\<some sort of flash player ID>\localhost\#orava\mutilate
If you can't find appdata, make sure hidden folders are enabled in folder settings, Windows might be hiding it by default.
You can also try using a software like Everything to instantly find files, simply search for "items.sol" and it'll show you all the custom item files.
To access the Flash Player right click menu, disable [Settings -> Misc -> Allow RMB] in MaD2 since it's overridden and bound to trigger by default.