Google App Engine DataNucleus “does not seem to have been enhanced” Issue

I got DataNucleus exception while developing a Google App Engine based Web Application for one of my office clients. Here is the error message.

javax.jdo.JDOUserException: Persistent class 
"Class com.xxxxx.xxxxx.domain.XXXXXUser does not 
seem to have been enhanced. You may want to rerun the 
enhancer and check for errors in the output."
has no table in the database, but the operation requires it.
Please check the specification of the MetaData for this class.
 at 

org.datanucleus.jdo.NucleusJDOHelper.getJDOExceptionForNucleusException(NucleusJDOHelper.java:375)
 at org.datanucleus.jdo.JDOQuery.execute(JDOQuery.java:252)

NestedThrowablesStackTrace:

Persistent class "Class com.xxxxx.xxxxx.domain.XXXXXUser
does not seem to have been enhanced.
You may want to rerun the enhancer and 
check for errors in the output." has no table in the database,
but the operation requires it.Please check the specification
of the MetaData for this class. org.datanucleus.store.exceptions.NoTableManagedException: 
Persistent class "Class com.xxxxx.xxxxx.domain.XXXXXUser does 
not seem to have been enhanced.You may want to rerun the enhancer 
and check for errors in the output."has no table in the database,
 but the operation requires it. 
Please check the specification of the MetaData for this class.

How to parse toString date value to Date object

I have some issue with toString date value parse to Date object. here is my solution for that.

     try {
 Date cutterntTime = new Date();
 String dateStringValue = cutterntTime.toString();
 //String dateStringValue = Thu May 05 11:26:49 IST 2011;
 DateFormat formatter = new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy");
 Date date = (Date)formatter.parse(dateStringValue);

 System.out.println("Date Value is : " + date);
     } catch (ParseException e){
 System.out.println("Exception :"+e);
     }