Hi Alan,
Just to summarize our communication on the subject:
Switching to another copy of OC made it better (Acquisition successful with some warnings).
A side note I got is that if OC 5.1 is installed over an uninstalled DFM 4.0, sometimes "ghost" objects appear.
Regardless - OC 5.1 is not fully supported for caching in 1.1.1, as the cache model is not complete.
WFA 2.0 contains a revision of OC 5.1 cache, while completing the missing objects.
Thanks,
Yaron