Giving you the benefit of the doubt in getting applet signing right, I'll bet the error you get with the signed applet is slightly different. If you look at the error you received:
java.io.FilePermission c:/Program execute
You can see that the command shell is considering the command to end with the first space. Since there's no command called "c:/Program", you'd get an error. Don't forget to purge your browser's cache and remove all instances of the class file from the class path so an unsigned copy doesn't get picked up. If all else fails, try working through the Signed Applet chapter of Advanced Programming for the Java 2 Platform. There may be a step in the process that you've missed.
hi, Joe Ess .thanks for ur replai, but still i am getting the same error.here problem is not with path i.e c:/program execute. i think problem is with applet security. pls help me to solve this problem.
Did you try going through the tutorial I pointed you to? And you will need to change that path. cmd does not like spaces in the path. You can either convert it to 8.3 notation (i.e. "progra~1" for "Program Files") or put quotes around the path.
thanks Joe Ess .for ur invaluable guidelines. now my signed applet is working .but it works only on stand alone system. if i try to open from some other systems through net it is throwing java.security.AccessControlException acess denied. pls help me how to overcome from this problem.