The headerrs already sent error means that there is some sort of output occuring on the page before the header function is used.
the error is reporting that the outpu started around line 51 of the options_Add.php page:
output started at /hermes/web###/b1067/server/PowerStore300/Admin/options_Add.php:51
if you are having dificulty locating the problem, please send a copy of the options_Add.php page in a zip file.