Are you going directly to Tomcat on the Linux box or via it's web server?
If it's via the web server (probably Apache), you may need to define the /forums URL as a TC webapp in the config file. (Note: some installs are set up to do this automatically every time TC and HTTPD are restarted).
You should also check to see if the forum web app is actually registered and starting. You should be able to do this with Tomcat's tools (newer TC versions use /manager/html can't remember if this is valid for 4.1). TC generally gives a different message than 404, but 4.1 might not.
An alternative to the webapp manager is to check the TC logs to verify that jForum is truely starting. You should see some info from net.jforum classes there.
Finally, 4.1 is ancient. [originally posted on jforum.net by monroe]
I installed JForum 2.1.6 on my windows test machine with Tomcat 4.1 and it worked flawlessly. I could create categories/forums/etc.
I then installed it in a Linux server box with the same Tomcat 4.1 and the install part seemed to work fine. But then when I'm redirected to /forums/list.page, I get the Tomcat HTTP Status 404 - Not found error page.
I've checked all the Tomcat log files and nothing looked suspicious. I verified that all files/directories under the jforum webapps directory are owned by the tomcat user so it shouldn't be a permissions problem.
Tom [originally posted on jforum.net by TomHj]
I'm going through Apache v2. I could tell the JForum servlet was up and running because I went through the post-install configuration step using the Web interface via Tomcat/Apache v2. I didn't think I needed to change anything else in Tomcat because the initial configuration was done via the servlet. I saw that install/* seemed to work fine during that post-install configuration step - so I'm not sure why the TC context would need additional configuration for forums/.
But going straight to Tomcat, everything works fine. So clearly the Apache/Tomcat interface is the problem.
As for Tomcat 4.1.... I know it's ancient... I'm installing JForum into a live production server with 100s of concurrent users hitting another custom servlet that I wrote. There just hasn't been a need to go to a newer version of Tomcat (yet).