Then i guess you are in some trouble. The file basically store information about actions and its parameters as well. So you can replace from any other Action but all your action will get renamed accordingly as Action1 or Action2 depending on which folder your pick it up from
You can create a new test with some actions.(Just Empty test with Actions)
Then you can copy the contents from the script.mts file into the respective actions. If you had local objects, then you can copy the ObjectRepository.bdb from the old action folde to the new action folder.