Squirrelmail's change password shows error message.Why ?

Dear All

In my squirrelmail-plugins, it is observed that 
change_password plugin was used. Earlier thorugh squirrelmail->
Options->Change password feature, the users were able to change
their own ldap password, but now when on tries to change their
passwords, the user gets the following error message:-


Change Password


We could not retrieve your old password from the LDAP server.




  
    
    
      
        Old Password:
        
      
      
        New Password:
        
      
      
        Verify New Password:
        
      
      
        
        
Please
give me some pointers to check why this is being displayed ? Which file
and which funtcion and which paremeters to check to avoid this error
message?

Give some pointers ?

Regards,

jmaan