I’ve successfully installed both versions on the same machine before. There are two key things: 1) make sure your root webMethods directory is different, and 2) ensure that the JVM you have installed is a version that is compatible with both versions. (See the README files for your particular versions for the compatible JVM versions.) In your case, though, you may want to just uninstall the 4.6 version first, since it’s an eval copy anyway.
#webMethods-General#Integration-Server-and-ESB#webMethods