i have installed a oacs-5-2 version with postgres 8.2 and ran into the same problems as you. There were actually two problems, both not easy to spot:

• ::xo::db::has_ltree was using an cache entry, bootstrap.tcl in 5.2 was not loading the -init file before the xotcl apps like it does in cvs head.
• there seems to be a difference in the error propagation from db_1row between 5.2 and head, the error messages are not reported, the catch seems bypassed. i rewrote the ltree test, such that catch is not needed.
please upgrade form cvs-head.

[02/Jan/2007:16:51:55][6857.1076447456][-main-] Error: Error sourcing /var/lib/aolserver/oacs52/packages/xowiki/tcl/xowiki-procs.tcl:
 during '::xotcl::__#3 contains'
    ::xotcl::__#3 ::xotcl::Object->configure
    ::xo::OrderedComposite ::xotcl::Class->create
    ::xo::OrderedComposite ::xotcl::Class->new
    invoked from within
"::xo::OrderedComposite new -contains [my cr_attributes]"
    (procedure "init" line 8)
    ::xowiki::Page ::Generic::CrClass->init
    ::Generic::CrClass ::xotcl::Class->create
    invoked from within
"::Generic::CrClass create Page -superclass ::Generic::CrItem  -pretty_name "XoWiki Page" -pretty_plural "XoWiki Pages"  -table_name "xowiki_page" -id_..."
    (in namespace eval "::xowiki" script line 6)
    invoked from within
"namespace eval ::xowiki {

  #
  # create classes for different kind of pages
  #
  ::Generic::CrClass create Page -superclass ::Generic::CrItem \
   ..."
    (file "/var/lib/aolserver/oacs52/packages/xowiki/tcl/xowiki-procs.tcl" line 9)
    invoked from within
"source $__file "

Thank You!