In the link darkstone provided, SomeWelshGuy indicates that FraNewItems.bsa is integrated into the new Francesco's Creatures and Items Resources - Items.bsa included with v5. He then goes on to say that you can either rename the file as with previous versions, or just leave it as it is. However, should you choose to rename it, you must deactivate the associate .esp file that carries the same name as the .bsa. IMO, it's probably better to leave well enough alone.
Unfortunately, I have not been able to get FCOM up and running myself. I still can't exit the sewers and enemy corpses are green. I am aware that these problems are related to missing resources, but the usual solutions don't work, i.e. see above. The real problem is all of the FCOM installation guides, as well as the readme's for the latest versions of the associated FCOM mods, appear to be out of date. Even the most recently updated guides still direct modders to perform steps that are no longer necessary, and even use patches that actually conflict i.e. Cobl for OOO and MMM, while others exclude patches that are necessary for certain mods like EVE HGEC and Harvest Flora for SI.
Sources:
http://www.somethingfornobody.com/wiki/index.php?title=Oblivion
http://www.oblivionmodwiki.com/index.php/FCOM
http://devnull.sweetdanger.net/fcomloadorderexpanded.html
http://forums.bethsoft.com/topic/1464623-relz-fcom-convergence-10/
http://www.gameskyrim.com/fcom-patches-compatible-with-fcom-t275557.html
EDIT:
So, it turns out it was my mistake:
Winrar couldn't extract the bsa's for multiple mods for some reason so, even though the files were there after repackaging them
for BAIN, they were emtpy (0 Kb). I was just about to give up when I just happened to notice this in the Data folder. I used 7zip
Instead, and now everything involving FCOM is up and running so far.