AdminCP>Paid Subscriptions error

[Stripercoast2]

Hi all,
Trying to get to the bottom of this one. Recently took over the Admin role on another board and have noticed that, when trying to access the "Paid Subcription Manager" tab in the AdminCP, I get the following screen. Actually I get this on any of the options under the Paid Subscriptions section, except for "Subscription Permissions" and "Test Communication".

Any suggestions on what I need to do to resolve this? The board was recently updated from 3.7.x to 3.8.7, and I'm not sure if this issue was there before that, or if that's when it started.

Thanks in advance for any tips!
Jake