When $wgLanguage=ca in LocalSettings.php, Modification_date property does not seem to be created. No problem when $wgLanguage=en. I haven't tested other languages.
These are some of the warnings I get when I repair/upgrade tables in this state:
<br />
<b>Notice</b>: Undefined property: SMWTimeValue::$m_errors in
<b>/homez.93/wikisofi/www/extensions/SemanticMediaWiki/includes/SMW_DV_Time.php</b>
on line <b>384</b><br />
<br />
<b>Warning</b>: implode() [<a
href='function.implode'>function.implode</a>]: Invalid arguments
passed in <b>/homez.93/wikisofi/www/extensions/SemanticMediaWiki/includes/SMW_DV_Time.php</b>
on line <b>384</b><br />
Version: unspecified
Severity: normal