I just had this problem not a week ago. Just call sprint and ask for advanced technical support. Explain your problem, and they should reset your username and password. When I formatted my hero is when the error began. It prevented any internet data from coming through. After they set it correctly, I can get online again.
Btw, your pcs vision username can be found in menu-settings-about phone-status. Then look under Current Username. Have them compare it to the one on their record. I know that when searching the web a lot of speculation about error 67 comes up, such as being caused by internet tethering, but in the end it all comes down to what it actually says. Your username or password is wrong. Hope this has helped and you get it fixed soon. that error is a serious pain.