[news.eclipse.platform.swt] Newbie: Help SWT error

[Roland.Goecke@xxxxxxxxxxxxxxxxxx (Roland)]

This is probably a dumb mistake but given that I have now spent hours
trying to fix it, I am at my wits end.

I am using Eclipse 2.1 on Win2000 with Sun SDK 1.4.1_02.

I am trying to write a program similar to the SWT examples file
'ImageAnalyzer' which I can compile and run without problems.

I cut and paste some parts into my program and it compiles without error.
However, when I try to run it, I get the following error message:

java.lang.IllegalArgumentException: Argument cannot be null
	at org.eclipse.swt.SWT.error(SWT.java:2318)
	at org.eclipse.swt.SWT.error(SWT.java:2262)
	at org.eclipse.swt.graphics.GC.<init>(GC.java:72)
	at ENoteGUI.ENoteGUI.open(ENoteGUI.java:115)
	at ENoteGUI.ENoteGUI.Init(ENoteGUI.java:57)
	at ENoteImageAnalyser.<init>(ENoteImageAnalyser.java:29)
	at ENoteImageAnalyser.main(ENoteImageAnalyser.java:34)
Exception in thread "main"

What does it mean? I copied the same directories into the classpath and
library path variables in the 'Run...' dialog that I find in the SWT
examples, in particular the swt.jar and the directory that contains the
swt-win32-2133.dll file.

Any help would be much appreciated!

Roland