large obiect in postgres 7.3

When i try to create lo type:
create type lo (
internallength=4,
externallength=10,
input=int4in,
output=int4out,
default='',
passedbyvalue
);

I get a error : function int4out(lo) does not exist ?????

I can't restore base from postgres 7.2....

Why ?

NETim