What is the exact error message; which class is it that Java cannot find?
What version of Java are you using and what version of Java is running on those other computers?
How are you trying to run the class on the other computers; as an applet via the browser, as a stand-alone program (your applet has a main method) or some other way? If you're running it from the command line, then what's the exact command you're entering?
NoClassDefFoundErrors are almost always caused by a wrong classpath. Did you set the classpath? Does the classpath include the directory that contains the class file for your program?
Is the file FtoC.class (the compiled class file, not the source file) available on the other computers?
also make sure that JVM should be of same version which you are using on your computer....this may be also one of the problem.......
but the most probably the problem is your class is not on build path.......
adding a class to a build path will resolve your problem.....
subject: No class def found error on other computers