Do you have a work exchange (MS Outlook) email account set up on your phone? Exchange allows companies to enforce all sorts of restrictions on your device when you set up a connection to their email server, including requiring a PIN or password, encrypting your phone, allowing remote wipe and, yes, disabling the camera. If that's what is causing it (and it sounds like it to me), this is the fist time I've heard of a company actually enforcing that provision.
If it is an exchange policy, you should have gotten a warning screen before it connected for the first time stating what policies were being enforced. And the only way to resolve it will be to uninstall that email account. But it couldn't hurt to ask your company's IT department if they really need to lock out the camera.