DarkRP I cannot upgrade Tomas Money Printers?

Okay so i have recently installed Tomas Money Printers.. They work perfectly apart from 1 thing, that is the "Buy" button to upgrade the printers.. Im pressing E on the "Buy" button but it just doesnt buy the upgrade. Not only that but the "Buy" button does not glow when looking at it as it is supposed to..

Does anyone know why this is? And how i can fix it? Please do help if you know! :disgusting: :disgusting: