Solder sticks to PCB (not just the pads!)
You've under-etched the board, or the photo resist was not properly exposed or developed to reveal the copper for etching (so it would definitely be under-etched in that case).  

The way it works is that the etch resist prevents the copper from being etched away. When you are done you should be able to see light through the etched areas (and there still should be resist protecting the traces). 

A photo would help, but it may be either that you did not recognize the appearance of an etched board or that something is funky with your etchant that is causing the areas being etched to not have a bright matte copper appearance. Here's a partially etched board where you can see the laminate partly exposed and the copper remaining.