problems downgrading

I was having problems with 9.2.0, so tried going back to the 9.1.0 patch. No luck there so I thought uninstalling the game altogether, then reinstalling it with 9.1 would work as I've done that with earlier games.

Now I'm getting a message

Could not use database location '/C/Program Files/Sports Interactive/Football Manager 2009/2009/updates/update-910/db/910' - reverting to the default location.

I've tried reinstalling several times and its still not working, so any help to get this working would be great as this is doing my head in. Its not even working with 9.2.0 now.