Ubercart Product Feature - Unable to select node type

Drupal 7.16
Ubercart 7.x-3.2

I tried to add pay-per-node as a feature to a product in Ubercart.

When on node/[NID]/edit/features/paypernode/add, I get the following message as an error:

Notice: Undefined variable: return in paypernode_get_types() (line 617 of sites/all/modules/paypernode/paypernode.module).

Additionally, there is no selection field under "Node type", only the text:

" Node type *
Node type the user will be allowed to create."

Trying to save the feature returns the error:

"Node type field is required."

This only seems to happen when no content types are selected. Looking at the code, it seems that it is supposed to show all of them in that case, but instead, it doesn't show any.