ERROR: dynamic load not supported

All,
This is with a new 7.3.4 installation. Every CREATE FUNCTION call I 
make, e.g.,

CREATE FUNCTION plpgsql_call_handler () RETURNS LANGUAGE_HANDLER AS    '<absolute-path-to-pg-install>/lib/plpgsql'
LANGUAGEC;
 

fails with this error. I know the specification of absolute paths for 
the library lookup is deprecated, but it's supposed to still work, and, 
as of last week, did. "I haven't changed anything." :) (But doubtless 
have done something stupid.)

Thanks for any advice.                          Rich Cullingford                          rculling@sysd.com