The startdwhouse is a perl script in pw/pronto/bin, that is used for starting things up.  
This error will occur if another startdwhouse script is running at the same time. Perhaps another startup process was occurring (by someone else, or some other automation). Please stop/kill startdwhouse to clear any hung processes.

e.g.
ps -ef | grep -i startdwarehouse  =>  Check the process id of startdwarehouse
kill -15 process_id =>  This will gracefully kill process
kill -2 process_id => This will interrupt process that is similar to ctrl-c
kill -9 process_id  => This will kill process

If the existing startdwhouse script cannot be killed/stopped, OS reboot is the last option to clear any hung processes.