I brought some of my work home with me, but when I try to run the program here, I get the following errors:

"SDClass.java": cannot find symbol; symbol : class JDOMException, location: package org.jdom at line 22, column 17
"SDClass.java": package org.jdom.input does not exist at line 23, column 23
"SDClass.java": package org.jdom.output does not exist at line 24, column 24
"SDClass.java": package org.jdom.output does not exist at line 25, column 24


Where can I find these packages and how do I get my program to know where they are?

They're not part of the standard installation. Depending on which implementation your course uses you'll have to download it from somewhere.

http://www.jdom.org/downloads/

go to the above link and first download the jdom.jar and then set the classpath accordingly