Try renaming the save game DAT and CMT files to scenario DAT and CMT files, drop these into the scenarios folder, and you MAY be able to extract the maps from the game, assuming it was not a PBEM (encrypted) save.
This technique is not guaranteed, as a game in play <> a scenario!. However - it
may allow you enough access to get the map extracted. Or, it may blow up in your face - you'll need to suck it and see I'm afraid.
Then, delete these scenario files as they are worthless for recreating the scenario.
Now, open the editor and load your newly-saved maps, and start creating your scenario again from scratch. Save to a new slot, and remember to keep back-ups in future !
Cheers
Andy