Failed to load library /home/bill/.Rack2/plugins/Borg/plugin.so: /home/bill/.Rack2/plugins/Borg/plugin.so: undefined symbol: _ZN4rack3app17ModuleLightWidgetC2Ev
it was working on the late november build. updated to the rack free beta 2 sdk and rack.
the error is reported for a dozen or so plugins from other sources, such as audible and bog audio
Did you remove old plugins and use versions compatible with the Rack build?