Java Development Tools

Hi,
I am newbie to JDeveloper and ADF.

Following is the complete scenario:-
Upon clicking of a menu link on left side a page is displayed with all Employee details data. I click on Employee Name and "Edit Employees" page is displayed. the user tries to modify details and clicks on "Save' button. Due to a unique field I show him an error message by adding to the Struts Action error object as following

errors.add("MRCError",new ActionError("error.message.alreadyexist","District Code"));
actionContext.setActionErrors(errors);
saveErrors(actionContext);

It displays the user the same edit page with the error message at the top.
Now if the user tries to click on any of the links of the left menu the following error is displayed on the top of page because of the following error:

oracle.jbo.DMLConstraintException: JBO-26048: Constraint "DST_UK" violated during post operation:"Update" using SQL Statement "BEGIN UPDATE Employee SET CODE=:1 WHERE ID=:2 RETURNING ID INTO :3; END;".

I am not sure why this update is being called now when I click on other links on the left menu.I have overridden the onCommit event.

Please help me out at the earliest

Thanks
Prashant