In my experience the pumpkin seeds need to be fresh. I think they will kill worms even when not so fresh because I was passing lots of 'threads' in my stool. See my post above.
When you buy your seeds make sure the seeds are smooth and clean looking - not broken and crumbling. Also, make sure the packet is not filled with air, you know, like a balloon, that makes me think there is gas (bacteria) in there.
Somebody recommended to me 'Raskal' for Tapeworm and I see one of the ingredients is pumpkin seeds.
I am now on the Dr Clark parasite cleanse - just the cloves and Black-Walnut tincture. I havent seen anything in my stool since! I think, if you want to see parasites you have to do enema as the parasites are semi-transparent and when washed (I mean enema) in a loose bowel movement you will see them.