I, too, was experiencing the issue with Adblock Plus where Flash Player would crash when video ads were displayed/blocked on Newgrounds.com, and for me, the fix was what mapx
suggested, which is to only have one instance of the Flash Player plug-in enabled.
To disable all but one instance of the Flash Player plug-in in Chrome:
1. Type ‘chrome://plugins/’ (without quotes) in the address bar
2. Click ‘Details’ in the top right corner of the page to expand Plug-ins list details
3. Click 'Disable' for all but one instance of the ‘Adobe Flash Player’ plug-in (the disabled instances will turn gray)
Click the image below to see the steps: