Worldpay gateway issue


Not sure if anyone can help?

Trying to set up Worldpay gateway with a new installation of Worldpay Junior.

When i configure worldpay I put in the installation id - I am not sure what the callback password is? So I left this blank.

When I test the worldpay through the site on Test-approved. I get a message redirect from worldpay as below:

Secure Payment Page

You have submitted a TEST request to a LIVE system - You can use the button below to continue on the TEST system.

I click the button to redirect to the Test system

and then get this error:

Secure Payment Page

Sorry, there was an error in processing this transaction:

Error initialising request:

* The information sent from the merchant’s site is invalid or incomplete. Please send the following information to the merchant:

The transaction cannot be processed due to the following:

o the merchant is not authorised to use Select for purchases

Server information 08/Dec/2009 09:41:41 Server ID mg4imscs4p (WPReq-216366)

Please can you help me get this set up. Worldpay is not new to us - we have used them for over 5 years. I have just set up a new installation id for this website.

Many thanks