Siyab, I'm so glad you brought this to my attention. I just found a book I've been promoting on Amazon.com where I earn a measly commission (I'm talking a very low $1.30!) and Google has the product with a $15 commission. Of course the person has to sign up for a free trial with their credit card but I'd much rather promote the book with the chance of earning $15 than what Amazon is paying.
I've been playing around with this and it's pretty neat. You can basically setup a customized group of ads to promote. The "no creative" message you got means there are no ads available that fit that size for that particular product. That's my assumption. For example if you found a product and select 234x60 and get that message that means the advertiser doesn't have an ad for that format.
This is going to be pretty slick once the ad database is filled.
