I think I had that error a while ago. I got the impression that somehow the .dtsx file had simply got corrupt. I started again with a fresh package, went through exactly the same steps and it worked perfectly that time. I suggest you stop trying to fix the old one, it is not worth spending days on it if it's some weird corruption that the normal interface cannot fix because it is not expecting it. If you have a backup of the package from before it got corrupt then use that as a starting point. If not and you have done a lot of work already you may be able to copy the other tasks from the original package to the new package to prevent you having to do it all again. If you simply don't want to lose the original script you might be able to open the .dtsx file in Notepad, then find and copy the text of the original script out of it.