C# batch file puzzlement

Question

OK here's one for you all. I have a batch file that calls a java class. The code in the batch file is: "java -cp . mypackage.JavaLooseCoupling". When I execute the .bat file from the command line it works fine. When I double click on the .bat file it works fine. BUT when I call it from my C# app (which is what I want to do) I get a java.lang.NoClassDefFoundError. Is this something to do with classpath? If so how do I go about setting it? I am using XP Pro, VStudio 2003, .net 1.1, Oracle Jdeveloper 10.1.3, J2SE runtime environment 5.0 Update 6. Thanks, Simon