Hi Gustaf,
The page has been visited many times before without errors. It's been returning this error for a couple months now. I anticipated finding the cause before now... =/
current xowiki version: 0.124 from cvs most recently updated 12 March 2010 as part of trying to resolve this.
The prior cvs version was from 7 September 2009, when I imported some xowiki instances from other websites (for use with host node mapping). It worked fine then.
other current versions:
xotcl-core version 0.112
modules/tcl/xotcl.tcl: aol-xotcl.tcl,v 1.15 2007/08/14 16:38:26
This is built on freebsd ports 7.3-PRERELEASE FreeBSD 7.3-PRERELEASE #5: Sun Feb 28 14:24:49 AST 2010
The cvs 2009-09-07 cvs upgrade was from xowiki 0.60.3 on cvs apparently around 15 or 16 January 2008 (according to file timestamps).