I am getting a viewpaneloader crash.

I also get crashes at other times, which I understand may be the result of an inappropriate plugin. I preview a lot of video.

Can you please tell me how to get back to the default plugins?

It's probably not the Opus plugins themselves and more likely a bug in one of the video codecs/splitters you have installed which the Movie plugin will be trying to use.

I'm not at my computer to provide a direct link but the FAQs on media playback and on crashes when viewing certain directories should both contain useful advice.

As a quick fix, you could disable the Movie plugin.