Now that you've found the problem, you should probably find a way to fix it. It looks to me like the weir(flapper) is sticking on the water bond(stainless plate in skimmer).
Can you put the weir back in (pump off) and see where it hangs up? If it is hanging up on he water bond, it should be straighforward to remove the water bond, bend the edge that touches the weir back a bit and replace it. Don't try to bend it in place, it's held in with one small bolt through a hole in your plastic skimmer - something will break before the plate bends. If you do this, be sure to replace the water bond it is critical to your pool's electrical safety.

If you're not comfortable with this ( or maybe to preserve warranty ) you may want to get your electrician back to fix the water bond - he should have installed it.

As far as start up chemistry, you're right, you need chlorine. Read through the stickies here and the guides on poolsolutions.com and make a plan. If you have questions, open a thread in the chemistry section. My #1 pool chemistry tip: Order a Taylor k-2006 test kit.