Moodle in English

yeah - sounds like moodlemlbackend isn't running right - the default username/password is hard-coded in that package - we've been building our own versions of the package and dropping it on an external server rather than on the local machine as we have multiple web front ends on most of our clients sites. (we also change the default password!)

I did find some of the MDLQA tests quite useful when debugging this stuff - take a look at this one to see if the steps shed any light:
https://tracker.moodle.org/browse/MDLQA-11576

good luck!