Explanation: (Note: This is different from the more common message "dbspawn/dbsrv12 set ERRORLEVEL = 1".)

If the "dbspawn/dbsrv12 set ERRORLEVEL = 0" message appears by itself, without any other error messages, it is probably safe to ignore; it is probably a false error which is sometimes displayed by the "debug" shortcuts used to start the Foxhound engine:

All Programs - Foxhound1 - Tools - Start Foxhound via Chrome - debug

All Programs - Foxhound1 - Tools - Start Foxhound via Firefox - debug

All Programs - Foxhound1 - Tools - Start Foxhound via IE - debug

See also...
dbspawn/dbsrv12 set ERRORLEVEL = 1