You are getting a java.lang.NoClassDefFoundError which does NOT mean that your class is missing (in that case you'd get a java.lang.ClassNotFoundException). The ClassLoader ran into an error while reading the class definition when trying to read the class.
Put a try/catch inside your static initializer and look at the exception. If you read some files there and it differs from your local environment it's very likely the cause of the problem (maybe file can't be found, no permissions etc.).