Comment 230 for bug 178038

I encountered this bug in both Lucid and Maverick, but the issue with flash on 64 bit systems is well known. Adobe Labs has released a new 64 bit version (alpha-level) of Flash for all platforms.

http://labs.adobe.com/downloads/flashplayer10.html

I removed the default flash that came with the Maverick upgrade and followed the instructions for installing the Adobe Square release. No further crashes with the npviewer and libflashplayer. The Square release does not use nswrapper.