404 and 500 errors

I upgraded a 5.1sp6 server to NW6.5 and am switching its use from being our
bordermanager server to our webserver for Groupwise WebAccess. With the
NW6.5 upgrade, I installed apache 2 and tomcat 4.1.18 that shipped with
nw6.5. I thought these were preconfigured to work out of the box but I am
having trouble and wonder if I am missing some config info.

I can display the welcome page and the iManager page and they are fully
functional. I can also display the tomcat server admin page and the tomcat
web application page but I cannot click on any of the links - I either get a
404 not found message or a 500 error that says "cannot forward after
response has been committed". Once in a while if I wait long enough,
clicking on a link will work ok but if I try it again, i will get the 404
and 500 errors.

Also, I cannot get to the <webserver ip address>\servlet\SnoopServlet to
make sure tomcat and apache are coexisting peacefully (I am told displaying
this page signifies this).

I noticed in my portalservlet.properties file that I did not have a
system.GUID number. I read somewhere that this is needed. In fact, prior to
doing a reinstall of apache and tomcat yesterday, I was getting a 500 error,
missing setting: system.Guid. That particular error was fixed by doing the
reinstall but I still do not have a system.GUID number.

I do not want to proceed installing GroupWise Web Access until I resolve
these issues. Has anyone experienced anything similar?

Thank you in advance
Stacie