404 page after upgrade

When upgrading 3.0 to 3.1 you can just upgrade immediately to 3.1, then go through all the change logs to make sure all the instructions are followed. There is a lot of repeated info in there, so it really does not take very long at all.

One thing to check is that (I hope you made a backup) in your original index.php there were no additional configurations. Also did you upgrade the index.php file? I also presume you have not altered the system core files at all. From memory I think there were some changes to the config file too, so it might be worth comparing the latest version of the config file to your current version.

Not a lot of help I know - sorry.

Best wishes,

Paul