I don't have a legal background, but in general
Americans use the word "government" in a much broader context than Europeans (and I believe Canadians as well). To Americans "the government" can mean the entire state apparatus (President, Congress, Courts, the Treasury, Fire and Police deparments, the Bureau of Prisons, the IRS, the Department of Education etc... where as the "Administration" refers to the body of elected officials sitting in Washington DC i.e. "The Obama Administration", "the Bush Administration".
It can therefore be confusing to Americans when they read or hear things like "Italy's Government Collapsed on Thursday". To Americans this sounds as if a state of war exists in Italy and that all or most public services have shut down.
For this reason I find the following NY Times Article rather interesting, and just from the title I am willing to bet that the author(s) is/are European. (Their names " IAN FISHER and ELISABETTA POVOLEDO" tend to give it away.)http://www.nytimes.com/2008/01/25/world/europ...
To Europeans the word "government" is more or less the same thing that Americans mean when they say "Administration".
So in a nutshell:
AE: administration = BE: government
AE: government = BE: the state
I believe that the German usage of "Regierung" follows the BE usage of "government", but we'll have to wait for confirmation of that.
I hope I am making sense.