We had this problem with DoubleClick’s Version 2 components, version 2.1.3. A buddy of mine lost hours of dev time trying to debug this problem – thanks Won!
After installing the .mxp everything appeared to work ok, but as soon as you tried to select the component and edit any of it’s settings in the Component Inspector, the radio buttons, check boxes & text fields in the inspector turned out to be totally unclickable.
The only solution that worked for us was to completely uninstall Flashbug add-on from Firefox. Disabling it didn’t work, we had to totally uninstall. It’s annoying, yes.