Last time I tested this extension I remember having to setup (unknown) settings in the company's paypal account to use the extension. You may have already done this and not mentioned it. <i>*shrugs*</i>
1) If your getting returned to your site's checkout page (Q: Is this the URI where you are returned ) ... 2) If your getting the "waiting on payment server" message +3 retries .... and then tells me to contact the site administrator ....
I would wager a guess; you might not be getting the expected response returned from paypal (payment success / failure code from paypal) after payment information entry and redirection back to your site's checkout. Though that guess is blind.
End result ... is because payment success is not being received upon return to checkout from paypal payment information entry. Since it's not being received the whole order/checkout is canceled at the end of 3 retries and the information is basically dumped as a failed transaction (I've run into this one before :P ).
//kracker
<i>Living Legends - The Truth (Swollen Members)</i>
I actually put in a test order to the site in your debug info (laughing @kracker ...)
I was able to start, add to cart, checkout, confirm, enter paypal payment information (using credit), submit payment information, print payment receipt, continue (back to checkout) to the Order 1 [Pending] screen.
From the user side this all looks like a successfully completed transaction.
If your missing backend records or other information I guess there could be more subtle problems...
Though it looks like you have already resolved your paypal payment breakdown ...
//kracker <i>Cake - Shallow Hal - Building A Religion</i>