Installing 3rd party addins
From OpenSimulator
This page explains how to install, update and uninstall 3rd-party addins for the simulator server in a systematic way. 3rd-party addins are packages created around region modules, possibly with additional external libraries and resources, that extend the simulator with additional functionality. Examples are ossearch (the simulator part), MISearch images, assorted money modules, etc.
Registry Location
Before you start using managed addins, it is important that you think carefully about where you want to keep them. Internally, OpenSim uses its own addins, and it installs the addin database under its bin folder. If you don't change anything, 3rd-party addins will be placed there too.