After successfully installation of JMS multisite component on joomla 1.5 .I follow the next step of installation of patches and also installed all the patches successfully ..But after this the site crashes and shows the following error:[an error occurred while processing this directive].Please give me some solution to overcome this error.
Thanks.

This "an error occurred while processing this directive" is an apache message.
Try get more info in the apache log file or contact your hosting provide to get more info on which directive would not be authozised.

Perhaps your apache forbid some call to some PHP functions that are executed at the installation. Without any information on the directive that is forbidden, we can just suggest you to search for additional logfile to get more info.