Client machines are running on Java 1.6_03 to 1.6_05. Here is the output from the command line:
C:\Temp>java -cp C:\Temp\ Thumbnail "C:\Temp\IMG_1503.JPG" "C:\Temp\ndthumbs\IMG_1503.JPG" 100 0
Exception in thread "main" java.lang.UnsupportedClassVersionError: Thumbnail (Unsupported major.minor version 49.0)
at java.lang.ClassLoader.defineClass0(Native Method)<br/>
at java.lang.ClassLoader.defineClass(Unknown Source)<br/>
at java.security.SecureClassLoader.defineClass(Unknown Source)<br/>
at java.net.URLClassLoader.defineClass(Unknown Source)<br/>
at java.net.URLClassLoader.access$100(Unknown Source)<br/>
at java.net.URLClassLoader$1.run(Unknown Source)<br/>
at java.security.AccessController.doPrivileged(Native Method)<br/>
at java.net.URLClassLoader.findClass(Unknown Source)<br/>
at java.lang.ClassLoader.loadClass(Unknown Source)<br/>
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)<br/>
at java.lang.ClassLoader.loadClass(Unknown Source)<br/>
at java.lang.ClassLoader.loadClassInternal(Unknown Source)