In addition to what Ben said, this is an area that's been fiddled with in various versions, including I believe in 7.0 (but I'm not sure, as I tend to take full advantage of being a native English speaker and ignore this issue :( )
You might check the hacker's group archives on www.postgresql.org, as there has been discussion of difficulties here, one advantage of an international group of developers. There's a big gap in the archives due to a screwed-up switch to Majordomo2 but you might find some help there, and in the documentation.
I strongly suggest you switch to 7.0 if possible, so you only have to figure this out once (until 7.1 comes out, at least!)
Also, 6.5.2 has the "always bang the disk with a write+fsynch to pg_log even on read-only selects" feature, which is death to the performance of systems like the ACS, not to mention the poor disk holding the database. 6.5.3 fixes this...
