title says it all, my mate gave me a 50mb mod, too bad its an omod. So i downloaded OBMM and i can install the damn thing, i click load, click the omod, and it says 'cannot find central directory' or something. Loads of help would be much obliged.

I your Oblivion directory you will find a folder obmm.
In that folder is one called mods. Put your unziped omod
in there. Start OBMM, and away you go.

OBMM is not a mod and does not install like a mod. It is a separate program that performs quite a few handy operations on Oblivion. It only needs to be run when you need to make a change, or want to run one of those handy widgets. Such as installing an OMOD.

The best place to start learning about what OBMM can (and can't) do as well as getting good info on installing and running it properly is the author's site, Here: http://timeslip.chorrol.com/

Hope this helps.

sorry dude, tried, failed