Visual improvement in error popup

Before:
![screen shot 2014-11-24 at 3 14 09 pm](https://cloud.githubusercontent.com/assets/1371296/5172765/9a46fa20-73f0-11e4-9fd5-fe7ab51f2e6b.png)

After:
![screen shot 2014-11-24 at 3 09 56 pm](https://cloud.githubusercontent.com/assets/1371296/5172764/9a3c92a6-73f0-11e4-9937-3e22c130065e.png)