This eclipsecoding FAQ page does confirm your diagnostic:
When the
CLASSPATH
gets too long, the program cannot be launched (at least under Windows) – try to shorten your classpath. In the case of a plugin, you can try to remove unnecessary required plugins.
And you have here a thread detailing the log errors.
Since you can launch Eclipse, but not the application, I would check if you don’t have too many plugins included in your launch configuration. Could you check if you have added only the required plugins?