Cannot create Task

dears

When i try to create a new task, i got the error 'Error

during process. Contact your system administrator'.

Please find the breif error log contents

java.lang.Exception:

at com.sap.workflow.es.template.WFTaskWizardDispatcher$TaskWizardDynPage.updateWFTaskObject(WFTaskWizardDispatcher.java:1637)

at com.sap.workflow.es.template.WFTaskWizardDispatcher$TaskWizardDynPage.createTask(WFTaskWizardDispatcher.java:1342)

at com.sap.workflow.es.template.WFTaskWizardDispatcher$TaskWizardDynPage.processItem(WFTaskWizardDispatcher.java:1316)

at com.sap.workflow.es.template.WFTaskWizardDispatcher$TaskWizardDynPage.onSubmit(WFTaskWizardDispatcher.java:1016)

at java.lang.reflect.Method.invoke(Native Method)

anybody got any answer, plz reply me

thanx in advance

kantha