Generally, as I remember it, Dev would make both OOO Full, and OOO Lite functional with FCOM.
In the case of 1.34, he hadn't gotten around to editing the Lite version with the new features, so it conflicted quite badly.
However, earlier versions should still be okay together, as far as I know.
edit: from Dev's website:
Oscuro's Installation
During installation of Oscuro's Oblivion Overhaul, you can normally use either the FULL version or LITE version, but currently the OOO 1.34 Beta does not include ther LITE version. This will be fixed in future releases so you can once again use the LITE version of OOO.