Some times if we delete the servers configuration in the workspace or if we move the workspace adding tomcat as server can become difficult thing. We will hit with the error Cannot create a server using the selected type.
To resolve this error, try one or all of the following:
1. Go to Window–>Preferences–>Server–>Runtime Environments and fix the broken path/link for the server
2. Rename the org.eclipse.jst.server.tomcat.core.prefs to org.eclipse.jst.server.tomcat.core.prefs.bak (or you can delete this file). This file can be found at workspace.metadata.pluginsorg.eclipse.core.runtime.settings
3. Rename the org.eclipse.wst.server.core.prefs to org.eclipse.wst.server.core.prefs.bak (or delete the file). This file also can be found at the same location as above