I had a similar issue on my joomla install. The buttons did not work and the check all option on the grid did not work either.

The reason for my issue was that I did not have access to the includes directory in which the javascript files are located. The joomla.javascript.js file was not being pulled in and as a result the buttons where not working as expected.

My access was set on the host site. Once that was updated everything worked fine.

Hope that helps.