ALTER TABLE sample SET TABLESPACE

Hello, I speak little English language but try to understand me.

I am running "PostgreSQL 7.4.1 on i686-pc-linux-gnu, compiled by GCC
gcc (GCC) 3.3.2 (Mandrake Linux 10.0 3.3.2-6mdk)" on a remote server
and running pgadminiii 1.8.0 RC1 on windows xp (ES)

When such change a "comment" on a table with pgadmin, the application
also try running:

ALTER TABLE sample SET TABLESPACE ;
COMMENT ON TABLE sample IS 'sample table';

but SET TABLESPACE is not valid in 7.4. I did not have this problem
with 1.8.0 Beta 2 (only executed COMMENT ON TABLE sample IS 'sample
table';)

It is possible to resolve this? Or is that no longer supports old
versions of postgresql.?

Thank you.
Ariel Giomi. ( Argentina)