I see an Age: Apr 01, 2001 (good) Alexa: 1,017,484 (bad) Google index: 72 (bad) Yahoo Backlinks: 162 (horrible) I can't see how a website that old has that few links. 1 order a month isn't too bad with those stats... You need to hit some SEO HARD. Content, Link building, Ads, etc...
Maybe advertisers do not believe in this type of websites. Two years ago I bought milions of banner impressions on different PTR websites. Most of them disappeared before my campaign finished, some of them took my money and didn't show single banner... so it can be problem of whole of the PTC niche.
That domain has only been active a few months, before that it was dollarsbyemail.com I've never known paid to sites to have any kind of quality content.
http://www.paidtoclick.com/ gets repeat advertisers and perhaps an order every three days on average. Sure there is a lot of frauds and unprofessionals in this industry.