Error: PayPal returned: You do not have permissions to make this API call

[EdenCrow]

Hi Guys,

I've got VirtuMart installed with Joomla! and am trying to use the PayPal module. I have tried to link this to my PayPal Sandbox account but when I test the button I get the following error: "Error: PayPal returned: You do not have permissions to make this API call".

Here are some screenshots of my setup in the PayPal configuration:
1) http://i.imgur.com/VTvNP.png
2) http://i.imgur.com/gNT6b.png

I'm new to Joomla! and VirtuMart so sorry if I've left out important information or have just done something stupid.

Thanks,

Eden Crow