I also tried to add it via the Watchdog
2014-08-19 14:20:09.567/xt$bridge/Schenker_SWORD_C2k/ERROR/onEntityAdd (bridgings): Exception creating bridging 'C2k_to_Tango': java.lang.NullPointerException
2014-08-19 14:20:09.567/SwiftletManager/ERROR/ConfigfileWatchdog/performTimeAction, got exception: onEntityAdd (bridgings): Exception creating bridging 'C2k_to_Tango': java.lang.NullPointerException
No, the problem was a different one. The bridge was not empty, it was after failover occured. So some time before the failure there was a sync error with the config. Trying to re-add the bridgeconfig via watchdog then brought up the null pointer exception I mentioned earlier in this thread.