500 error page: Display "add mailto" option to create a ticket for the new user.
email to: IT-Support@abc.com
subject: SEC_Windchill new user account
body: Please create account for this user.
Here is where you have all the error files from Apache
You can consider putting a java script popup ( you can write in error.jsp) that displays the message what do you want to display followed by re-directing the URL to your company support site.