Can you access the files directly?
If so you need to activate the handy dandy template path hints.
Just go into your magento admin.
Go to System > Configuration > Current Configuration Scope > Select Default Store View (or what you default named your store)
When it has activated the scope of the Default Store go to Advanced > Developer > Debug > Template Path Hints > Yes
Then go to System > Cache Management and Disable all the Cache.
Now go to the front end and view the page you want to have changes on.
You will see this:
Take note of the paths by taking a screenshot or listing down the paths.
Go back to the settings and do the Default Store go to Advanced > Developer > Debug > Template Path Hints > (Set to) No
You will then have the reload the page at the frontend without the path hints.
Use the paths to find where you need to copy the file from or edit the theme file.
And when you are done editing and everything is working fine.
Go back to the cache and enable them again.