You can restore proper functionality, allowing the easy method of auto-installing MyGunDB through Chrome by taking the following steps:
Type chrome://plugins into your address bar in Chrome.
On the settings page that loads, click the Details button in the top-right to show more options
Under the Flash item (which will probably appear first), the first subitem will include “PepperFlash” in the path.
Click Disable to disable this version of the plugin
The “PepperFlash” item will now be grayed out – Flash will still work for you
Restart Chrome and the auto-installation feature should now work properly.