Tone down error message text

From this: 

![web_pay](https://f.cloud.github.com/assets/1514/1254670/44795d10-2b79-11e3-9a91-81ed5fb31d0a.png)

To this:

![web_pay](https://f.cloud.github.com/assets/1514/1254985/88d7eda6-2b7d-11e3-9365-0348e73e5990.png)