Definately an infection in the bottles. But on the bright side, you've got some drinkable bottles from your first batch, which is more than can be said for many of us.
Nothing wrong with onestep. If you've got some infected bottles and some good bottles, chances are the infected ones weren't clean enough to be sanitized in the first place. If they're not perfectly clean, it's not possible to sanitize them with any chemical sanitizer. (My personal favorite sanitizer is iodophor, especially for beginners.) It's a pain in the ass, but try a little more brush work with those bottles.
One other thought. You are sanitizing your bottle caps, right? I don't understand it, but some people don't think it's necessary. I do think it's necessary.
