Last modified: 2011-04-30 01:20:37 UTC
Notice index does not exists line 1245 Proposal replace : ###### ORIGINAL LINE ######### $datePreference = (string)$options['date']; ###### REPLACE BY ############ if(array_key_exists('date',$options))$datePreference = (string)$options['date']; else $datePreference =''; ##############################
Date is defined in $wgDefaultUserOptions in DefaultSettings.php, so it looks like yours is not up to date or is corrupted. On a side note the code should probably use getDefaultOption instead of doing it manually.
Fixed in r64263.