It's been a problem, because we then can't single out where the problem actually is. So I tried my hardest to discover the problem. And I think I found it.
The error messages are in the translation strings, and they're easily fixable: (en, en_LJ)
I'm pretty sure that ".error.invalidmpasw" refers to "error - invalid maintainer password" while ".error.invalidpassword" refers to "error - invalid community password", though that's not what the English (en) version says.
Can someone check this out and make the necessary changes? (I'll love you foreeeeeeever.)