I'm not the creator of mirror mode so I can't provide more accurate insight into this problem but judging from the error message you can try the following
1. Install the latest JDK
http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
2. Make sure the JAVA_HOME environment variable is set on your system
Windows:
Press super + r
start cmd
execute the command "where java"
Linux:
execute "which java"
The output should contain a line for the JDK folder, not only JRE (if you also have JRE installed)
3. Go to {JDK}/lib/ and look for the file tools.jar which contains the Attach API used to attach to Java processes
If this one is missing, you can find it on google but it should be included in the JDK
Make sure the JVM you are attaching to is supported by mirror mode