Worldpay Support in General Add-Ons Support Posted June 12, 2003 I am not an expert on sessions but I think this error occurs when you attempt to write the same session id twice to the sessions database which doesnt allow duplicates. There is a whole pile of reasons why this might happen - in the case of WP, my belief is that when you are retuning to your store from WP, your current session has become inactive after being written to the sessions database so when the session id is returned by WP, the store attemps to rewrite it to the database again, and so gets an error. To resolve, you need to discover why the active session is being lost whilst you are at Worldpay or why the store attempts to restart the same session again. e.g. do you have cookies turned off? Are you moving away from the hosting server? Are you retuning to a html page rather than php etc etc? I dont think this is a fault generated by the WP module - it is probably just that you only discover this fault when using WP.