Classifieds: Subscribers Cannot Create Ads and "Catchable fatal error..."

My "Classifieds" plugin and WPMU installations are up to date. I'm trying to make Classifieds function properly, but I have encountered a couple of problems.

Problem 1: Catchable fatal error . . .

When attempting to view any created ad, I see this error:

Object of class WP_Error could not be converted to string in [abridged]/public_html/ on line 914

See an example here.

Problem 2: Subscriber Cannot Create Ads

I've edited the Subscriber role's permissions in both Classifieds>Settings and CustomPress>Content Types>classifieds. However, when I attempt to create an ad with a verified Subscriber account, I receive this message:

You do not have sufficient permissions to access this page.

Any insight on either issue would be deeply appreciated.