Did you try opening Oblivion Mod Manager, going to Utilities -> Archive Invalidation -> make sure box is checked for BSA Alteration -> make sure box is checked for Textures -> make sure box is checked for generate Archive invalidation entries on hash collision -> click on update now
Noooo! - Please people stop suggesting BSA Alteration especially to new people who dont even know what it is. BSA Redirection is the safe option that works.
If the OP now decides the machine these are being used on cant cope and decides to un-install QTP3, the Oblivion - Textures - Compressed.BSA which is now ALTERED will not be referenced by the game for those textures, ever again, without a clean re-install of the original games BSA. Result = Lots of textures missing replaced by pink everywhere.
Oblivion looks in "Oblivion - Textures - Compressed.BSA" file for its textures (its like a zip full of files), if you install replacer textures like QTP3 you need to use an archive invalidation method... so far so good.
There are two that work. Alteration, and Redirection.
Alteration is only good if you know 6 months down the line exactly how many and which textures you invalidated with this method (and maybe complicated that even further by overwriting those overwrites with individual files from other mods), and how to reverse the process (and just in case it all goes pete tong have a backup of your original bsas' before using Alteration)
Redirection is the safest method and works.
Its also the default method in OBMM and Wrye Bash, for this very reason.
Reference here - http://devnull.sweetdanger.net/archiveinvalidation.html