Trouble upgrading to 7.2.3

[Luca200]

I have just installed PostgreSQL 7.2.3 and I need to load it with a dump from 7.0.2, but when I submit my dump I get an error.
After the install, I created the data directory with

mkdir /usr/local/pgsql723/data

,
then

chown postgres /usr/local/pgsql723/data

(obviously postgres user did already exist).
After that, I made initdb (by postgres user) and then started postmaster (by pg_ctl).
Finally I tried to restore my db with

/usr/local/pgsql723/bin/psql -d template1 -f restorefile

and I get an error that's something like "I cannot create a database because some other users are connected to template1" (I'm sorry I don't have the exact error text, but I didn't work on this machine when I got it).
This is the beginning of the dump:

\connect template1
select datdba into table tmp_pg_shadow       from pg_database where datname = 'template1';
delete from pg_shadow where usesysid <> tmp_pg_shadow.datdba;
drop table tmp_pg_shadow;
copy pg_shadow from stdin;
root	29	t	f	t	f	\N	\N
callcenter	27	t	f	t	f	\N	\N
nobody	28	t	f	t	t	\N	\N
\.
delete from pg_group;
copy pg_group from stdin;
callgroup	1	{26,29,27}
\.
\connect template1 callcenter
create database &quot;callcenter&quot; with encoding='SQL_ASCII';
\connect callcenter callcenter

It gives me the first error in "create database callcenter", stating that some other users are connected to template1; then it gets a fatal error when it tries to connect to that db (obviously!).
The strange matter (to me) is that some months ago I loaded the same 7.0.2 backup to version 7.2.1, and it worked perfectly.
Help...?!?!?