New to Java

Hello,

I am new to Java. I am taking a course in algorithms and an exercise is to write a simple stack and queue.

I installed JDK 1.6.0.21, and then installed Eclipse Helios SR1 x86_64. I am running on Windows 7.

I created a new project in Eclipse, added a class with a main(), and wrote a simple stack implementation.
When I do CTRL-F11 the Java application runs successfully, and the output is shown in the console window.

When I do F11 (to step through the code) I get this error:
(in message box) Cannot connect to VM [socket closed]

in the console window it says:

FATAL ERROR in native method: JDWP No transports initialized, jvmtiError=AGENT_ERROR_TRANSPORT_INIT(197)
ERROR: transport error 202: connect failed: Permission denied
ERROR: JDWP Transport dt_socket failed to initialize, TRANSPORT_INIT(510)
JDWP exit error AGENT_ERROR_TRANSPORT_INIT(197): No transports initialized [../../../src/share/back/debugInit.c:690]

Any ideas of why I cannot launch the debugger?