Sometime, eclipse has problems with the target platform. Cannot be loaded etc.
There is not a general solution, but one solution with a high probability to work is:
1) Open the target file with an text editor.
2) Increase the sequenceNumber (e.g. by one):
<?pde version="3.8"?><target name="Odysseus Target Platform" sequenceNumber="1502128610">
3) After saving, eclipse should show something like "Loading target components" ... do not use eclipse at this time, as it may lead to problems
4) Open the target file with the target editor again and click on "Reload Target Platform"
I'm not able to execute an Odysseus script. The execute script button is disabled or I get a NotEnabledException.