Thread:Project:Support desk/Problems with extensions

I want to install the extensions: Unfortunately, all of these extensions did not work properly with unknown problems.
 * Extension:User_Merge_and_Delete
 * Extension:DeleteBatch

After the installation steps in above pages, I tried to use them in Special pages, but the browser return 500 errors with the extension pages.

I checked the error log in apache2, and error messages are as follows:

PHP Fatal error: Call to undefined method UserMerge::getUser in /var/lib/mediawiki/extensions/UserMerge/UserMerge_body.php on line 26 PHP Fatal error: Class 'Html' not found in /var/lib/mediawiki/extensions/DeleteBatch/DeleteBatch.body.php on line 145

The environment was: MediaWiki	1.15.5-7 PHP	5.3.10-1ubuntu3.5 (apache2handler) MySQL	5.5.29-0ubuntu0.12.04.1

What are the problems? Is there something wrong with my installation? Or the extensions?