[eclipse-dev] cannot launch eclipse help

[Daniel Bertin <danielb@xxxxxxxxxxx>]

Hi all
I just subscribe to this list. hope it's the correct one.
I installed eclipse 2.1 and have been using it happily for about 1 month. 
then all of a sudden I cannot launch the application. I get the message
"problem during startup check the .log file in the .metadata directory of 
your workspace"
In the .log I find message;
problems occurred when invoking from plug-in "org.eclipse.core.runtime"
stack 0
org.eclipse.core.internal.dtree.objectnotfoundexception: tree element
/tools/examples/src/quote.java not found
but quote.java is there in the directory.
why can I not launch eclipse no more????
I install the newer 2.1.1 and the same I cannot launch it.
am  running eclipse 2.1 on mandrake 9.1
what is wrong
Help please someone
Daniel