(I may take a pix if my
description isn't good enough for you to figure out what I am doing wrong)
it is obvious that it isn't purl. It looks like one row, here and there, is purl
and the rest are knit. The back side looks all knit.
I think a picture would help immensely. If your front is all knit, as you say, then the back automatically should be purl, since the back of a knit is a purl.