Success: 151
Failed: 1168
Why is that?
Start by watching the videos in under support on the help tab. There is so much scrapebox can do that its hard to say where the best spot to start is.
What I would do is mess around with some of the features. Don't go crazy and blast a million blogs out the gate, do a few hundred and get familiar with the way things work.
As for the success/fail you asked about. Scrapebox scrapes the search engines for results. It supports fast posting to the most common setups and slow poster to many more. Not every url that search engines return necessarily relevant to what you searched for. (go figure)
So if you search for wordpress blogs on golf, you will find a lot, but you will also find stores selling golf stuff, golf articles etc... Obviously scrapebox can't post to them, so they would fail. Some blogs dont have comments turned on so they would fail, some have setting enabled that it would make it impossible to post, etc... So you will have a fail rate, but its a number game. If you post to a million blogs and 600K fail, you still posted to 400K which is smokin awesome!
Stick with it, you will get it.
The second thing I would do is spend a week reading thru this thread and pay particular attention to anything sweetfunny or gregstereo says.