It shouldn't be trying to 'create' the file. Have you tried "Save as" and specifying the correct folder in My Documents?

No, I just went through and checked an it's trying to save in the right place, I don't understand why it's trying to create a file either?!

Do you think uninstalling and reinstalling might help?

It's possible that could help. You might want to make sure you back up your savegame files first, to be safe. You can see the procedure here. (Those are the procedures for VV3, which is what you said you're playing, even though this is a Fish Tycoon thread).

Reinstalling worked great Unfortunatly I'd left my tribe on 2x speed and they were all dead by the time I got everything sorted again But I'm starting afresh!

We usually suggest a reinstall only as a last resort, but it will usually restore all game settings to the default and allow the game to run again. I'm glad you got the game working, although I'm sorry it took so long that your tribe died.

I did all of this and there are no problems with my computer.
I did not ever change from windowed mode to fullscreen, so I don't know what the problem is.
I still get this error.

So I did the ldw step because that sounds like my problem exactly, but when I go to save the file it says I don't have permission to open this file, and tells me to see the owner of the file and obtain permission. Help!