A common response when you start/increase a workout is for your muscles to retain water. This increase in your lean mass can lead to little change (or even an increase) in the scale, even as you are burning fat.
However, muscle and water are considerably denser than fat (check www.dailyspark.com/blog.asp?post=quiz_how_
for a great photo of this), and typically this shows up as inches lost, even if the scale is being unco-operative.
Using the tape, rather than the scale, is a much better means of tracking your progress.