I always had the same problems. Of course, I don't use Netbeans anymore. I use IDEA.
However, it would probably be easiest if you could hold off until April and get Netbeans 3.6 which will be bundles with Tomcat 5. They do have a beta release of that version but I'm not 100% sure it already has Tomcat 5 in the beta version or not. An RC is due out this month.
Here is some more info.