i am an independent contractor/installer of variuos windows and doors. i have also done many service calls for manufactures and distributers in the area of minneapolis, mn. 99% of the time the window or door is installed incorectly, installer error. i know that you and the people in your development won't get too far on a class action lawsuit, as the manufacture has made an effort to correct the problem. my advice to you is to talk to the builder and have them fix the problem. the manufacture won't have any liability unless there is some gross negliance shown on their part. good luck!