Thread:Project:Support desk/Fatal exception of type MWException/reply

http://www.mediawiki.org/wiki/Thread:Project:Support_desk/Error_when_installing_MediaWiki. and http://www.mediawiki.org/wiki/Thread:Project:Support_desk/Fatal_exception_of_type_MWException_after_install_MW_from_1.21.0 seem to cover this problem and potential solutions.