Uh oh. This doesn't sound good. The broken file message that you're seeing is probably due to changing something in the pds file when you opened it and saved it with your text editor.

Since we don't know what you changed, this is going to be difficult to figure out. But let's assume that whatever you did happened at the beginning of the the pds text file. This is where your cursor would naturally land on.

In the first few lines a healthy pds file would look like this:

Content-Type: multipart/related
--- partseparator
Content-Type: text/AEFF
Content-ID: movie-layout
--- separator

You might have added or deleted a line or character when you opened the file. If the beginning of your file differs a lot from this example, the pds file is probably corrupted beyond repair.

I tend to like to open files with notepad just to see what's in them out of curiosity, but I never save the file, but you already know that now.