Java program won't open for some users

I created a Java program that quickly changes my laptop's IP address for me. It works great on every machine I test with, so I distributed it to my co-workers so they can use it. However, one of the technicians cannot open the program. I have confirmed that he is using Java Version 1.7.0, but when he double-clicks on the program (I packaged it as an .exe with Launch4j) nothing happens. Even if he tries to work as an administrator. I wrote a short Hello World program that opens a new window and simply displays "Hello World" to test it in Java. This program works fine. It runs Win 7 x64 just like me.

I believe this is a security setting in Java that the java.lang.Runtime.getRuntime () command doesn't like. exec (), but I've looked through all the settings and can't imagine which settings are blocking the program from running.

Can anyone give me any ideas on what I should be looking at?