You could tell us what the error is if you do not post links and logins to your site.
I have good vision but not good enough to read a blurry error on a 150x120 pixel thumb posted here.
exec has been disabled on your server by your host. That means you can not use Imagemagick, jpegtran or jhead. You can under global options in admin make sure you clear the lines for jpegtran and jhead and use gd2 as your image processor and you will be fine.