I am almost there. Everything worked in sandbox mode and I am now trying to go live on my development site.
I got my API credentials, registered the application and received an API ID.
I can process simple donations without a problem.
However, when I try to process an advanced payment, I get the following error:
Your pledge of $1.00 is almost complete.
There was a problem connecting with the paypal gateway. (CODE)550001 User is not allowed to perform this action.
I noticed that someone else had this problem, said he fixed it but did not say how.
I have triple checked all the emails, ids, etc. No extra spaces, periods, etc. that I can see.
Thanks for your help.