bunltd - 12:25 am on Apr 6, 2012 (gmt 0)
If your content isn't geared towards selling what the affiliate link offers, it likely won't result in much for you. Also, less than 100 clicks on a progam isn't a much to work with - if you figure a low conversion rate, it's not surprising that you didn't have any commissions. (There's more to the story, since you didn't mention what the click through rate was to the offer.)
Look at it on a per site/niche/program/offer basis, not lumping it all together, that way you'll have a better idea of where and what to focus on.