DPS New Zealand - webage not found http404

[MudSpud]

I was wondering if anyone would be able to help me.

I'm installing DPS (Direct Payment Solutions) into my shopping cart.

 

I've downloaded and installed the dps_pxaccess.php payment module.

I've managed to load it and everything works (credit card details etc get accepted) until it comes time to redirect back to the shopping cart website I get a 404 error telling me the page cannot be found.

 

The URL address its looking for is correct www.mywebsite/file_name/catalog/checkout_process.php. and is loaded on the website, but its just not processing and redirecting back.

 

Has anyone else come across this? Any help at all would be appreciated.

PLEASE HELP!!!!