Midori 0.5.8 reports error at launch and crashes often, particularly on pages with flash videos

[G.M.]

$ midori
sh: 1: /usr/lib/nspluginwrapper/i386/linux/npviewer: not found
sh: 1: /usr/lib/nspluginwrapper/i386/linux/npviewer: not found
*** NSPlugin Wrapper *** ERROR: failed to execute NSPlugin viewer
*** NSPlugin Wrapper *** ERROR: failed to initialize plugin-side RPC client connection
*** NSPlugin Wrapper *** WARNING:(/build/buildd/nspluginwrapper-1.4.4/src/npw-wrapper.c:3556):invoke_NP_Initialize: assertion failed: (rpc_method_invoke_possible(g_rpc_connection))

<opening a youtube page and after ~2 seconds of video playing>

Segmentation fault

$ midori --version

Midori 0.5.8 ((null)) Midori
GTK+ 2.24.23 (2.24.23) Glib 2.40.0 (2.40.0)
WebKitGTK+ 2.3.91 (2.4.2) libSoup 2.44.2
cairo 1.13.1 (1.13.1) libnotify 0.7.6
gcr No granite No

Copyright (c) 2007-2013 Christian Dywan

Please report comments, suggestions and bugs to:
        https://bugs.launchpad.net/midori

Check for new versions at:
        http://www.midori-browser.org

$ ls /usr/lib/nspluginwrapper
ls: cannot access /usr/lib/nspluginwrapper: No such file or directory

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[John Scott (fuzzytoothpaste)]

I was just playing a YouTube video on my old Dell Dimension 3000 (old video card) and it kept crashing. It happened over and over again. On Lubuntu 14.04 x32.