Broken screen door corners.

Do you drill these plastic style sliding screen door corners out like you would a metal one? They are staked twice. Also, where do I find replacements as the sliding screen door frame does not go together flush and standard replacements would effect the door fit and operation?

Thank you Dave. I was able to remove the old corners that I could get channel-locks on, and just knocked the others further into the frame with no drilling required. I bought 4 of the corners and 20 of the screws you suggested. All went together without a hitch. I do not think I needed the screws but hey, they're in there for more support. Thank you SWISCO. No one else offered the exact corners required to fix my families screen door.