So I need to make a back up and re upload the file.
What are you upgrading from...??
Then you just need to use the changed files package from the blog, and upload the contents so it overwrites your current files.
So I upload the package to my file manager and it will overwrite the files that are bad?
Yes, Unzip the Change-Files.zip in your forum's root, and it will overwrite the existing automatically. No need to run the upgrader.
unzip put in fm then leave it right...
You just need to download the changed files, un-zip them, and upload them to your forum root (main forum directory, containing the admin folder etc), overwriting the existing files.