After updating my system to FreeBSD 7.0, I received the following error from Opera:

Opera encountered a problem during plug-in setup.
Plug-ins will not work properly.
Check your installation.

Could not locate plug-in 'libnpp.so'.
This executable is included in the install package.

This executable is included in the install package.

Could not start plug-in executable 'operapluginwrapper'
/usr/local/share/opera/plugins/operapluginwrapper

Plug-in path
(Path can be modified in Preferences dialog)

/usr/local/share/opera/plugins

Some searching brought me upon a post in the offical Opera forums. For reference purposes, I will archive it here. To solve the problem, follow these steps:

• Close Opera
• Use root to edit the file /etc/libmap.conf (create it if it does not exist)

• Add the following lines:

  [operapluginwrapper]
  libXThrStub.so.6 libXtst.so.6
  

After a restart, Opera should work fine now. Apparently, only the wrong library is used to start the plugin wrapper, the lines above should fix this.