I had the same issue as oldshoe running the HelloWorld demo from the site. I tried switching the JRE as SyRenity (tried js2dk 1.4.2_19 as EclipseME recommends), but without success. Moved to Eclipse 3.3.2 with the same EclipseMe and Sun WTK and had no problem. Not a problem for me to use 3.3.2 (so far), but posting the details for anyone else having issues...
Problem came while running the following development:
Eclipse 3.4.1
EclipseMe 1.7.9
Sun WTK 2.5.2_01
Console Output:
Running with storage root C:\...\DefaultColorPhone
Running with locale: English_United States.1252
Running in the identified_third_party security domain
java.lang.ClassNotFoundException: org/kalmeo/tutorial/HelloWorld
at com.sun.midp.midlet.MIDletState.createMIDlet(+29)
at com.sun.midp.midlet.Scheduler.schedule(+52)
at com.sun.midp.main.Main.runLocalClass(+28)
at com.sun.midp.main.Main.main(+80)
Execution completed.
3335802 bytecodes executed
19 thread switches
1667 classes in the system (including system classes)
17251 dynamic objects allocated (514636 bytes)
1 garbage collections (0 bytes collected)

