rc4, restore of a db with psql freezes without warning if plpythonu is needed, but is not installed

I tryed to load a database dumped from version 7.4.3 which has a
function written in plpython.
The process seems to freeze at a "Create function" when I used psql and
the text-version of the dump.
After installing plpythonu it works.
psql should print an error-message indicting that plpython (or what pl
ever is needed) should be installed with creatlang before loading this
database.

Regards
Christoph Becker