[GENERAL] Error creating function

[Rebecca Clarke]

Hi

I'm doing a restore into Postgresql 8.4, postgis 1.5.1 and I'm getting the
following error when it creates the below function:

pg_restore: creating FUNCTION _get_buffer(geometry, double precision,
integer)
pg_restore: [archiver (db)] Error from TOC entry 966; 1255 49162661 FUNCTION
_get_buffer(geometry, double precision, integer) postgres
pg_restore: [archiver (db)] could not execute query: ERROR:  SQL function
cannot accept shell type geometry
    Command was: CREATE FUNCTION _get_buffer(_geom geometry, _radius double
precision, _density integer, OUT the_geom geometry) RETURNS geome...

I don't understand what 'cannot accept shell type geometry' means? Can
anyone help my lack of knowledge?

Thanks

Rebecca