I use Tomcat 6.0 and Eclipse 3.0 under Linux and I try to deploy a WAR in Tomcat. The problem is that the server is managed by Eclipse and I have some Eclipse project deployed.
If all you have is a binary WAR (no source code), it cannot be installed within Eclipse. This can happen in certain scenarios outside of normal development workflows. Here's the work-around solution:
tomcat-users.xml
file to enable adminhttp://localhost:8080/manager/html