DJ-MediaTools ver. 188.8.131.52
There was a fatal error in the component views related with missing 'visible' table column. It occurs on fresh installation of 2.7.0 and 2.7.1 versions and it can be fixed by completely reinstalling the DJ-MediaTools package.
If you want to keep the component data you can also manually add the missing column to #__djmt_items table by running the following sql query from your phpMyAdmin interface:
ALTER TABLE `#__djmt_albums` ADD `visible` TINYINT( 1 ) NOT NULL DEFAULT '1' AFTER `published`, ADD INDEX ( `visible` );
Note that you have to replace the #__ table prefix with your joomla table prefix.