Severe bug with postgresql 7.0.3

I use a DIGITAL ALPHA DEC2000 AXP500 with 128MB of RAM, architecture EV4
150MHz processor. I installed a Debian potato (2.2) and got problems
during installation, postmaster not starting.
After a mail exchange with postgres Debian mantainer, got sources of
postgresql version 7.0.3 (debian patched) and compiled, installation was
successful. Created a database with "createdb test", all OK. Created a
new user with "createuser gunny", all ok. Connected to test with psql
and create a very simple table named "prova" with only a column of
varchar(20), all ok. After did the command "\d prova", the problem is
that it never ended without message. With a ps I found the process
"/usr/lib/postgres/bin/postgres test idle" that get all the CPU but
little memory (4%). Some ideas?