If you are getting errors on your import lines (the first two you have noted) means your package cannot find the imports. You will need to add them to your class path. That is basic Java, and you will need to understand that to get this to work. You get your third error because it is reliant on on of the imports that is failing.
Also, you are calling a deprecated version of iText (based on the lowagie import), so you will need to use the current one. It is open-source.
Looking at your code, it does not seem to comply at all with the examples I'm scanning at https://code.google.com/p/flying-saucer/ you will need to review the requirements there to get to what seems to be your end-goal.
Cheers,
Brian