Glanced briefly at your log. You seem to have a bunch of web pages, plugins, podcasts etc. loading. Looks like JR is trying to load a page from PRI.Org which is not (or no longer) a public page -- might be wrong but this is putting the program into a loop and looks like the cause of this last crash.
Also it is using a facebook plugin? Seems like it worked (spotify login??) but running FB through JRiver or anything other than a browser is going to cause some kind of crash eventually in my experience at least.
In any case it seems totally web related as their is no crash in the recent log indicating video, or audio playback, or loading the GUI etc.
If you were using these extensively without a hitch in version 19, either the page at PGI is the problem (simple fix just remove it) or you might want to try switching to Chromium as I see you have JRiver load Internet Explorer. Loading non media webpages is often better using the launch in another window option ... if the page crashes it won't crash JRiver that way.
Hope this helps and welcome to the forum.