Dimension Pro random clicks when selecting presets/presets won't load

I seem to be getting more and more of these, though the behavior seems totally random.

I'll be browsing through presets, clicking on one and then I'll get a loud "click" and the selected patch just won't play. 

Moving on to the next patch, I get a similar "click" but then that new patch will play just fine.

If I then revert to the patch I've previously tried, it may or may not play.

As if something prevented patches from properly loading, but totally random. 

For exemple, the 1st Dimension patch loaded just fine a few minutes ago. I started browsing through different ones and when I got back to that first patch, it failed to load and only gave me that loud click. 

A few more attempts at loading other patches then back to the initial one - now it works...

Any idea?

Using Logic 9.1.8, on OS X 10.6.8.