If you are having permissions problems try this:
Click ONE time on the problem drive's icon to select it.
Type "command-i" to bring up the "get info" box for the drive.
At the bottom of the get info window, there is an area for "sharing and permissions". If it is not "expanded", click the "disclosure arrow" to see its contents.
After you do this, click the lock icon at the extreme bottom-right and enter your administrative password.
Now, put a checkmark into the "ignore ownership on this volume" checkbox.
Close the get info window.
Do things improve now?
Let us know the results.