PostGreSQL 8.1.0 : out of memory during vacuum full analyze

Hello,

This is my first posting in this mailing list and I am a PostGreSQL newbie.
I realize a benchmarck on PostGreSQL on a 300Gb database. I used the
release 8.1.0.

I have created my database, which contains 8 tables, loaded each table
and created the appropriate indexes.
Then, on each table, I have launched the "VACUUM FULL ANALYZE" command
as a non-root user.

This command failed on the last table, the biggest, called "lineitem"
which contains 1799989091 rows (near 300 Gb of datas).
Three hours after having launched the command, I've got this error :<>

<>TPCH=# VACUUM FULL VERBOSE ANALYZE lineitem;
<>INFO: vacuuming "public.lineitem"
<>*ERROR: out of memory*
DETAIL: Failed on request of size 67108864.

I do not try to launch again a vacuum full analyze on this table.

Can someone tell me why this error appears ?
Thank you for your help.

Regards,
Alexandra DANTE