you might want to try openacs-5.7, postgres-9.1, tcl-8.5.x and aolserver-4.5.1 or 2.
Openacs won't use that one new feature of tcl (the '(*)' thing) for awhile; the tcl peeps say tcl 8.4 is hanging and I'm sure pg wants to put 8.anything to bed.
I have an openacs-5.7 running on pg-8.3 in staging, it's looking good; I'll be moving the data model to 9.1 to try it out shortly.
