~ It might say that it's an 'Old File', well, here's the answer :
If you get an error message about "Old file not found", first check that you downloaded the correct version of the patch (Shivering Isles and vanilla Oblivion have two different patches). The other reason for this error message is that you previously installed one of the Shivering Isles beta patches. Any PC users who installed the first Shivering Isles beta patch (version 1.2.0410) need to uninstall and reinstall Oblivion in order to install the final version of this patch. This problem also occurs if you are using the Direct2Drive version of Shivering Isles as the current patch is not compatible with it.
Ok, I'm running Oblivion GOTY version. I've been trying to install and load mods with no sucess. I decided to try installing the Shivering Isles patch and recieved the "old file" error that was mentioned. So twice I unistalled and reinstalled my game, and still no change. I don't know how to tell if my version of Oblivion is already patched or not, but as of yet I am having issues installing and using mods. I need help! As of yet I have not found a thread that directly applies to my situation, so I'm looking to the rest of you for help.
There are many causes about the mods not working...
Make sure you got the latest Oblivion patch, then install SI, then patch SI. If the problem still persists.. it's beyond me