Powerload doesnt work

I have the EGO ST1521S with Powerload.  The first time I used it, it worked great.  I thought it was awewsome!  Today I needed to reload.   I threaded it throught, as per instructions, using the extra roll of string provided by EGO.  Hit the button for Powerload, it acts like its supposed to be loading but the string doesn't wind up at all.  Help!