Compiler can't find other classes

Question

I've got this bad problem that's been bugging me all weekend, and I can't work out how to fix it. A few months ago I was able to write classes that use other classes I've defined no problem. I just started using my compiler again, and now when I want to use different classes I've written, the compiler says that it can't find the other class:
D:\uni\2005 Sem2\cse12ipj\assignment\HabitatModule.java:12: cannot find symbol
symbol: class Module
public class HabitatModule extends Module
^
1 error
Tool completed with exit code 1
I've compiled the Module class and it doesn't have any errors. I'm guessing that there's something wrong with the classpath variable. Is that right? I'm using java 5.0.

Answer 1

This is the base class. It compiles fine.
public abstract class Module
private char type;
private String axisCode;
private Module moduleList;
abstract int getSpareCapacity();
When I compile this next class, the compiler on my PC says that the class Module can't be found:
D:\uni\2005 Sem2\cse12ipj\assignment\Habitat.java:12: cannot find symbol
symbol: class Module
public class Habitat extends Module
^
1 error
Tool completed with exit code 1
public class Habitat extends Module
private class Person
private String name;
private int id;
private String speciality;
private int maxPeople;
private int nrPeople;
private char subType;
private Person personList;
private String purpose;
public Habitat(int maxPeople, char subType, String purpose)
this.maxPeople = maxPeople;
nrPeople = 0;
this.subType = subType;
this.purpose = purpose;
public int getSpareCapacity()
return maxPeople - nrPeople;
If I compile it on any other machine, it's fine. I was looking on the web, and the CLASSPATH doesn't have to be changed for classes in the same directory.