I tested purchasing several products from my new cart at http://www.neuton.net/shop

But after clicking the Paypal button (for payment) I get the following error message . . .

" Error while storing data: Cannot create new route. "

What to do?

I'm getting the same error on your cart. Hmmm...I would open a support topic with Coffeecup. This time of night you'd probably get a faster answer.
Just go to your name on the top menu and scroll down to 'Your Support Room'. Open a ticket with Coffeecup. Give them all the information you can and I'm sure they can help you sort that out.

The issue here is with permissions:

http://www.neuton.net/shop/ccdata/php/servertest.php

Writable Directory Test
WARNING - Could not open '/home/neuton/public_html/shop/ccdata/php/../store/test.tmp' for writing. Some Shopping Cart Creator Pro functionality (e.g. the stock control) and some payment gateways (all except PayPal and Google Checkout) depend on being able to store data on the server. You should not ignore this warning

I turned off inventory tracking (and transaction logging) - republished the cart, and now it seems to work ok.

I don't really need inventory tracking. I used it because I like the little "Sold out" image that appears on sold-out items.
Is there a way to manually put that image on a product (without losing the product's original image)?
I see that the blue scanner at http://www.neuton.net/shop/viewcategory.php?groupid=0 remains "sold out" even after turning off inventory tracking(?).

BTW permissions for www.neuton.net/shop (where the cart is) are the following:

/shop = 755
/shop/ccdata = 755
all 10 subfolders under /shop/ccdata = 755
all other folders under /shop are also = 755

To use inventory tracking what permissions need to be changed (and to what)?

I am having the same problem with www.irismoon.com/shop
it is Hosted on GoDaddy.
any tips on what to change in configuration to allow the proper permissions?
Thanks in advance.
Art Graham
Ambassador

Art, I also have GoDaddy hosting. Shop works great.
I ran the php test on your site and got this error...

I took a look at my site, after I activated inventory....you should have a directory /yourshop/ccdata/store/ that needs permission 705. Check that and see what you've got.