Dr.Watson httpd.exe error

Dr. Watson error occurring when restarting the Netscape Enterprise Server 3.6 service. The error was directed towards the httpd.exe application that runs Netscape Server. Basically, the httpd.exe process did not always terminate so when the service would start up again, it would receive the DR. Watson error. this was preventing the service from starting. We were having to reboot the servers to get them running properly but after some time, the error would occur again.

Does anyone know why this error would occur and how to rectify the problem?