The crash you are experiencing has been fixed in 1.30.0.23. It is due to a NULL pointer returned on creation of the script debug floater which is created when a script crashes in an object around you (or in your own attachments), and this because of a bogus floater definition:
To work around this bug, and until you can get an updated version, simply replace the bogus XUI floater definition file with this one:
It must replace the one in CoolVLViewer1.30.0.22.app/Contents/Resources/skins/default/xui/en-us/