Leasing plane error - can't lease planes

I have plenty of money in my bank but every time I try to lease a plane I get an error message and it keeps going way down the page. What is going on?

[size="1"]An unexpected error occured![/size]

[font=Verdana][size="1"]Please see stacktrace below:[/size][/font]

[font=Verdana][size="1"]org.springframework.dao.DataIntegrityViolationException: Could not execute JDBC batch update; nested exception is org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update

org.springframework.orm.hibernate3.SessionFactoryUtils.convertHibernateAccessException(SessionFactoryUtils.java:621)

org.springframework.orm.hibernate3.HibernateTransactionManager.convertHibernateAccessException(HibernateTransactionManager.java:717)

org.springframework.orm.hibernate3.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:586)

org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:662)

org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:632)

org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:314)

org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:116)

org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)

org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:621)[/size][/font]

Could you please send the complete! message to support@airlinesim.aero, and pleas include Server, USername and Airline.

Please describe also, what you where doing, before this message occured. Are you using multiple browser tabs?

Thanks!