vastav bro..E-Verify is a free, internet-based system operated in partnership with the Social Security Administration that helps employers to determine the employment eligibility of newly-hired employees...

You can go for opt extension from the school with STEM, however to be eligible for OPT extension, the company u r working needs to be enrolled in E-verify program.Many companies like mine do not want to expose their information to federal programs,so they do not agree to participant in such programs.

for more information : http://www.dhs.gov/xnews/releases/pr_1207334008610.shtm