Help with multiple file projects

Hi everyone, I have a multiple file project for a class assignment.
It consists of a class Point, then a class Polygon which uses the
Point object, then a class Picture that uses the Polygon object.
Unfortunately, I cannot compile Polygon.java, because it cannot
recgonise the Point object. Any ideas? (I'm using the Sun SDK 1.4.2)
Thanks! (By the way, the drawing package and Canvas class were
created by my instructor to make drawing to Graphics easier)

Point.java:
**
* Point.java
* ----------
* Defines the base class for the drawing exercises
*/

package csc812;

import drawing.*;

class Point
{
private int m_iXValue;
private int m_iYValue;

// Default constructor
public Point()
{
this.m_iXValue = 0;
this.m_iYValue = 0;
}

// values constructor
public Point(int x,int y)
{
this.m_iXValue = x;
this.m_iYValue = y;
}

// Copy constructor
public Point(Point P)
{
this.m_iXValue = P.m_iXValue;
this.m_iYValue = P.m_iYValue;
}

// Calculates the distance between this and a given point
public double distance(Point p)
{
return Math.sqrt((m_iX Value-p.m_iXValue)*(m _iXValue-p.m_iXValue) +
(m_iYValue-p.m_iYValue)*(m _iYValue-p.m_iYValue));
}

// Draws a line between this and the given point
public void DrawLine(Point p,Canvas c)
{
c.drawLine(m_iX Value,m_iYValue ,p.m_iXValue,p. m_iYValue);
}

// Outputs the coordinates - primarily for debugging
public void dump()
{
System.out.prin tln("(" + m_iXValue + "," + m_iYValue + ")");
}
}

Polygon.java:
/**
* Polygon.java
* ------------
* This class uses the Point class to draw a polygon based on the
given points
* One critical assumption we make is that element 0 of the array list
is the
* starting point of the drawing
*
*/

package csc812;

import java.lang.*;
import java.util.*;
import java.awt.Color;
import drawing.*;
import csc812.Point;

class Polygon extends Point
{
// Declare an ArrayList, since we cannot predetermine how many
elements we will have
private ArrayList m_List;
// foreground colour is part of the polygon
private Color m_ForeColour;

// Default constructor
public Polygon()
{
m_List = new ArrayList();
m_ForeColour = Color.BLACK;
}

// Constructor
public Polygon(ArrayLi st List,Color cl)
{
if (List.contains( Point))
{
m_List = new ArrayList();
m_List = List;
}
else
{
System.out.prin tln("Polygon constructor error");
System.out.prin tln("The ArrayList passed is not of type Point, so
cannot construct object");
}
m_ForeColour = cl;
}

// Copy constructor
public Polygon(Polygon p)
{
m_List = new ArrayList();
m_List = p.m_List;
m_ForeColour = p.m_ForeColour;
}

// Draws the polygon
public void Display(Canvas c)
{
// Declare array for use
Point [] pArray = new Point[m_List.size()];
pArray = m_List.toArray( );

c.setForeground Color(m_ForeCol our);
for (int i = 0;i < pArray.length;i ++)
{
try
{
Point p1 = new Point(pArray[i]);
Point p2 = new Point(pArray[i+1]);
p1.DrawLine(p2, g);
}
catch(ArrayInde xOutOfBoundsExc eption e)
{
break;
}
}
}

// Sets foreground colour
public void SetColour(Color f)
{
m_ForeColour = f;
}

// Output for debugging
public void Dump()
{
// Declare array for use
Point [] pArray = new Point[m_List.size()];
pArray = m_List.toArray( );

for (int i = 0;i < pArray.length;i ++)
{
Point p = new Point(pArray[i]);
p.Dump();
}
}
}

Error messages:
Polygon.java:19 : cannot resolve symbol
symbol : class Point
location: package csc812
import csc812.Point;
^
Polygon.java:21 : cannot resolve symbol
symbol : class Point
location: class csc812.Polygon
class Polygon extends Point
^
Polygon.java:38 : cannot resolve symbol
symbol : variable Point
location: class csc812.Polygon
if (List.contains( Point))
^
Polygon.java:63 : cannot resolve symbol
symbol : class Point
location: class csc812.Polygon
Point [] pArray = new Point[m_List.size()];
^
Polygon.java:63 : cannot resolve symbol
symbol : class Point
location: class csc812.Polygon
Point [] pArray = new Point[m_List.size()];
^
Polygon.java:66 : cannot resolve symbol
symbol : method setForegroundCo lor (java.awt.Color )
location: class drawing.Canvas
c.setForeground Color(m_ForeCol our);
^
Polygon.java:71 : cannot resolve symbol
symbol : class Point
location: class csc812.Polygon
Point p1 = new Point(pArray[i]);
^
Polygon.java:71 : cannot resolve symbol
symbol : class Point
location: class csc812.Polygon
Point p1 = new Point(pArray[i]);
^
Polygon.java:72 : cannot resolve symbol
symbol : class Point
location: class csc812.Polygon
Point p2 = new Point(pArray[i+1]);
^
Polygon.java:72 : cannot resolve symbol
symbol : class Point
location: class csc812.Polygon
Point p2 = new Point(pArray[i+1]);
^
Polygon.java:73 : cannot resolve symbol
symbol : variable g
location: class csc812.Polygon
p1.DrawLine(p2, g);
^
Polygon.java:92 : cannot resolve symbol
symbol : class Point
location: class csc812.Polygon
Point [] pArray = new Point[m_List.size()];
^
Polygon.java:92 : cannot resolve symbol
symbol : class Point
location: class csc812.Polygon
Point [] pArray = new Point[m_List.size()];
^
Polygon.java:97 : cannot resolve symbol
symbol : class Point
location: class csc812.Polygon
Point p = new Point(pArray[i]);
^
Polygon.java:97 : cannot resolve symbol
symbol : class Point
location: class csc812.Polygon
Point p = new Point(pArray[i]);
^
15 errors