The search feature is the only thing lost by removing those files. Does the folder /Data/Sites/1/index exist? If not create that folder and make sure its writable and then try restoring those files, then do a search to initialise the index, then try editing.
I'll try some more experiments here tomorrow and see if I can figure out a solution. If you get any good error message post it. It should work in medium trust, that setting about the folder location is usually all thats needed to get it working.
Hope it helps,
Joe