I too have just started knitting again after a long time, and I'm having a problem - one of the patterns I'm trying to work has a YO P2, I can't seem to get this right and end up short of stitches at the end of the row. Can you help?
Yarn-overs before purls can be tricky. Just be sure the yarn is FORWARD before starting the purl. If it's in the back, your yarn over is not complete. In effect, you are wrapping the yarn over twice before a purl.
Do a regular YO then move the yarn to the front for the purl, just like switching it when doing regular knit/purl ribbing.