http://jira.xwiki.org/jira/browse/XE-391 I believe this issue occurs when there is only one initial revision to a Niels Mayer, http://nielsmayer.com<http://jira.xwiki.org/jira/secure/ViewProfile.jspa… a comment - 08/Mar/09 19:04 - edited I believe this issue occurs when there is only one initial revision to a document, and 'history' is selected and attempts to diff between version 1 (which exists) and version 2 (which doesn't). The code needs to be special-cased for this http://en.wikipedia.org/wiki/Off-by-one_error#Fencepost_error Here's some recent examples, caused by search engines: 2009-03-03 14:44:16,472 [/xwiki/bin/view/XWiki/SchedulerJobClass?viewer=changes&rev1=$%7Brev1%7D&rev2=$%7Brev2%7D] [TP-Processor35] ERROR api.XWiki - Failed to read versioned document org.suigeneris.jrcs.rcs.InvalidVersionNumberException: ${rev1} at org.suigeneris.jrcs.rcs.Version.<init>(Version.java:120) What's with scheduler job class? one revision: History of SchedulerJobClass Version Editor Date Comment 1.1 NielsMayer.com Administrator Dec 15, 2006 03:45:59 GMT-08:00 Another: 2009-03-07 03:24:39,164 /xwiki/bin/view/XWiki/WebPreferences?viewer=changes&rev1=$%7Brev1%7D&rev2=$%7Brev2%7D] [TP-Processor6] ERROR api.XWiki - Failed to read versioned document org.suigeneris.jrcs.rcs.InvalidVersionNumberException: ${rev2} at org.suigeneris.jrcs.rcs.Version.<init>(Version.java:120) What's with WebPreferences? One revision: Version Editor Date Comment 1.1 NielsMayer.com Administrator Apr 20, 2007 09:17:52 GMT-08:00 Niels http://nielsmayer.com