The most probable causes are that the SDK is not properly installed, the path variable does not contain the directory where the javac command resides, or you may not have read/write permissions for some directory or file.

Try logging in as root (on linux) or as administrator (on Windows).  If this solves the problem, then you need additional permissions.  Check that the path variable is properly modified to include the /bin directory where the javac executable is located.

If you see a message similiar to the one below:

msg> Compiling Runtime….

msg> javac failed with an Exception:

CreateProcess: javac -verbose -classpath C:\Kmax_9\ADC1054647171796;C:\Kmax_9\Extensions\Classes\;  C:\Kmax_9\Extensions\Classes\;C:\KMAX_9~1\Kmax.jar; C:\Kmax_9\ADC1054647171796\Runtime.java error=2

msg> Error while compiling the Runtime class…

It is an indication that the Kmax process cannot find the javac tool specified in the "Toolsheet Properties" dialog under the "Compiler" tab.