If the operation fails with SQL errors, the database user employed by your wiki (check your LocalSettings.php) probably does not have sufficient permissions. Either grant this user additional pemissions to create and delete tables, temporarily enter the login of your database root in LocalSettings.php, or use the maintenance script SMW_setup.php which can use the credentials of AdminSettings.php.
MediaWiki:Smw smwadmin permissionswarn
From Metabolonote
