Inherited object class not being recognized? (Old homework, new computer)

Last semester I had an intro to java class, this semester I have an "advanced" java class with another professor. An assignment I have for the current class bears some similarity to one I did last semester so I thought I'd fire up the old homework and see what I could recyle. However, the old homework won't compile now.

Maybe it's related to the fact that I had a different development environment last semester. I don't remember what version of SDK etc I was using last semester; my hard drive exploded and I had to start over again this semester. This semester's prof is also having us use J2EE, which I didn't last semester. Even so, it looks like a REALLY straightforward compilation error... doesn't recognize an inherited object class I had created, though that class itself compiles fine... the files are there and I know it worked last semester. What gives? I'll paste the code for the 3 classes that make up the app, starting with the driver class & working my way down, along with the compilation errors for each.

----------

/*
Project 5-1: Use inheritance to display a student record
*/

import javax.swing.*;
import java.text.*;

public class StudentApp
{
      public static void main(String[] args)
      {
            String identificationNumberInput, majorInput, gradePointAverageInput;
            CollegeStudent userCollegeStudent;
            String userInput = "";

            try
            {
                  while (!(userInput.equalsIgnoreCase("x")))
                  {
                        identificationNumberInput = JOptionPane.showInputDialog("Enter college student's ID:");
                        majorInput = JOptionPane.showInputDialog("Enter college student's major:");
                        gradePointAverageInput = JOptionPane.showInputDialog("Enter college student's GPA:");
                        userCollegeStudent = new CollegeStudent(Integer.parseInt(identificationNumberInput), Double.parseDouble(gradePointAverageInput), majorInput);
                        userInput = JOptionPane.showInputDialog(userCollegeStudent.toString() + "\n\nPress Enter to continue or 'x' to exit");
                  }
            }
            catch(NullPointerException e)
            {
                  System.exit(0);
            }
            System.exit(0);
      }
}

C:\j2sdk1.4.0_01\bin\StudentApp.java:14: cannot resolve symbol
symbol  : class CollegeStudent  
location: class StudentApp
            CollegeStudent userCollegeStudent;
                ^
C:\j2sdk1.4.0_01\bin\StudentApp.java:24: cannot resolve symbol
symbol  : class CollegeStudent  
location: class StudentApp
                        userCollegeStudent = new CollegeStudent(Integer.parseInt(identificationNumberInput), Double.parseDouble(gradePointAverageInput), majorInput);
                                                         ^
2 errors

Tool completed with exit code 1

----------

/*
Project 5-1: Use inheritance to display a student record
*/

public class CollegeStudent extends Student
{
      public static String major;

      public CollegeStudent()
      {
            identificationNumber = 0;
            gradePointAverage = 0.0;
            major = "";
      }

      public CollegeStudent(int userIdentificationNumber, double userGradePointAverage, String userMajor)
      {
            super(userIdentificationNumber, userGradePointAverage);
            major = userMajor;
      }

      public String toString()
      {
            String collegeStudentInfoString = "Student number: " + identificationNumber
                                                      + "\nGPA: " + gradePointAverage
                                                      + "\nMajor: " + major;
            return collegeStudentInfoString;
      }

}

C:\j2sdk1.4.0_01\bin\CollegeStudent.java:6: cannot resolve symbol
symbol  : class Student  
location: class CollegeStudent
public class CollegeStudent extends Student
                                    ^
C:\j2sdk1.4.0_01\bin\CollegeStudent.java:12: cannot resolve symbol
symbol  : variable identificationNumber  
location: class CollegeStudent
            identificationNumber = 0;
                ^
C:\j2sdk1.4.0_01\bin\CollegeStudent.java:13: cannot resolve symbol
symbol  : variable gradePointAverage  
location: class CollegeStudent
            gradePointAverage = 0.0;
                ^
C:\j2sdk1.4.0_01\bin\CollegeStudent.java:25: cannot resolve symbol
symbol  : variable identificationNumber  
location: class CollegeStudent
            String collegeStudentInfoString = "Student number: " + identificationNumber
                                                                       ^
C:\j2sdk1.4.0_01\bin\CollegeStudent.java:26: cannot resolve symbol
symbol  : variable gradePointAverage  
location: class CollegeStudent
                                                      + "\nGPA: " + gradePointAverage
                                                                                      ^
5 errors

Tool completed with exit code 1

----------

/*
Project 5-1: Use inheritance to display a student record
*/

public class Student
{
      public static int identificationNumber;
      public static double gradePointAverage;

      public Student()
      {
            identificationNumber = 0;
            gradePointAverage = 0.0;
      }

      public Student(int userIdentificationNumber, double userGradePointAverage)
      {
            identificationNumber = userIdentificationNumber;
            gradePointAverage = userGradePointAverage;
      }

      public static double getGradePointAverage()
      {
            return gradePointAverage;
      }

      public static int getIdentificationNumber()
      {
            return identificationNumber;
      }

      public static void setGradePointAverage(double userGradePointAverage)
      {
            gradePointAverage = userGradePointAverage;
      }

      public static void setIdentificationNumber(int userIdentificationNumber)
      {
            identificationNumber = userIdentificationNumber;
      }

      public String toString()
      {
            String studentInfoString = "Identification number: " + identificationNumber
                                                      + "\nGrade point average: " + gradePointAverage;
            return studentInfoString;
      }
}

[this compiles fine]