WrpEdit will open any of the .wrp files form the Operation Flashpoint Worlds folder.
These files are in the format OPRW as opposed to the format used by WrpTool which is 4WVR.
OPRW is the format used by the game and 4WVR is the 'unbinarised' format, if you like.
So, if the format you are trying to load is from OFP's World's folder, it should work with no probelms........4WVR on the other hand will not load into WrpEdit.
Planck