What version of GlassFish Server are you using? What operating system and version? What JDK version? Many problems are caused simply because system requirements for the release are not met. Refer to the Oracle GlassFish Server 3.0.1 Release Notes for the latest information regarding system requirements, and make sure your system meets those requirements.
What resources does your system have, such as memory, disk, and swap space? If system memory is an issue, look for ways to optimize your configuration and consider taking other actions such as adding memory or decreasing system load.
Have any patches been applied? If so, what are the product and operating system patch numbers?
What other products and technologies are installed and being used in the installation?
How many application servers, web servers, and directory servers are installed? What are the products and versions?
How is the web server connected to GlassFish Server? On the same system?
How is GlassFish Server connected to the directory server?
What JDBC driver is being used to access the database?