Error calling self-made plpgsql function "function XYZ(bigint) does not exist"

Hi

I have problem calling my function (prety easy):

== sql begin ==
CREATE OR REPLACE FUNCTION "InventGroups_GetAllParents"(int8) RETURNS SETOF "ItemGroupRelationNode" AS
$BODY$declare      R      RECORD;      SR     RECORD;
begin    FOR R IN select ItemGroupId, ParentItemGroupId             from InventGroups where ItemGroupId = $1 and
ItemGroupId> 0    LOOP        RETURN NEXT R;        --FOR SR IN select * from InventGroups_GetAllParents( 
R.ParentItemGroupId::int8 )        --LOOP        --    RETURN NEXT SR;        --END LOOP;    END LOOP;    RETURN;
end;$BODY$ LANGUAGE 'plpgsql' VOLATILE;
== sql end ==

"ItemGroupRelationNode" is a complex type
====
CREATE TYPE "ItemGroupRelationNode" AS  ("ItemGroupId" int8,   "ParentItemGroupId" int8);
====

The result is:
=========
select * from InventGroups_GetAllParents(0::int8)
=======
ERROR:  function inventgroups_getallparents(bigint) does not exist
HINT:  No function matches the given name and argument types. You may
need to add explicit type casts.

Thanks for responce