regardless of whether you check out opensim from a source repository or are using prebuild packages, opensim will always bring along its own libsecondlife.dll. as of the time of this writing this libsecondlife.dll is the subversion 1550 snapshot from libsecondlife’s subversion repo.

as mentioned in an earlier post, opensim’s libsecondlife sources are not contained within the main opensim source tree, you need to check those out separately:

% svn co http://opensimulator.org/svn/opensim-libs/libsl1550 opensim-libs

then, just go into the newly checked out opensim-libs directory and run nant to build libsecondlife.dll…

% cd opensim-libs
% nant

…and once it’s done, copy bin/libsecondlife.dll to your opensim/bin directory.

done. enjoy.