Why the margin call?

Hi all, i know this is a very noob question, i have completed the school of pipsology, but clearly my understanding of Margins is wrong.

I have a £1k demo account with Pepperstone 30/1 leverage. I have one open trade @ 0.1 lots with a stop-loss of 10 pips and just got a Margin call? Can someone please explain this to me? I have attached a screenshot showing my balance / equity and Margin.

I do have an pending order too, 0.1 lots but thats not even close to be fulfilled.