[News.eclipse.foundation] BreakpointValidationException whenever attempt

[jonathan.woods@xxxxxxxxxxxxxxxx (Jonathan Woods)]

I'm using Eclipse 3.0.1 on Windows XP Professional running on top of J2SE
1.4.2_06 (the SDK component).  Whenever I try to set a breakpoint in Java
source, I get "internal error: BreakpointValidationException".  The
Eclipse error log says:

!ENTRY org.eclipse.core.runtime 4 2 Oct 19, 2004 09:17:12.943
!MESSAGE An internal error occurred during: "Breakpoint location
validation".
!STACK 0
java.lang.RuntimeException: J2SE 1.5 parser not implemented yet
	at org.eclipse.jdt.core.dom.ASTParser.convert(ASTParser.java:714)
	at
org.eclipse.jdt.core.dom.ASTParser.internalCreateAST(ASTParser.java:681)
	at org.eclipse.jdt.core.dom.ASTParser.createAST(ASTParser.java:574)
	at
org.eclipse.jdt.internal.debug.ui.actions.BreakpointLocationVerifierJob.run(BreakpointLocationVerifierJob.java:109)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:66)

yet I'm not using J2SE 1.5.  Anyone have any ideas?

I did have debugging working fantastically in Eclipse 3.0 - e.g. remote
debugging of building processes and Tomcat web apps - so this is a bitter
blow!  I suspect that I managed to screw up configuration somewhere -
possibly around the time I tried out J2SE 5.0 on the same machine, though
I have since completely deinstalled J2SE and checked that no corresponding
folders exist, then reinstalled 1.4.2.  The problem happens still if I
switch back to Eclipse 3.0 or go up to 3.1; and it was happening with J2SE
1.4.2_05 too.  Everything else Eclipse-wise works fine.

Is there perhaps something cached in Eclipse history which has hung around
in the workspace?  If so, what should I clear?

tia

Jon