If you happen to be a roaming Telus customer that has a BlackBerry DTEK60 (or potentially other models), and you’re getting a bit frustrated because your mobile data is not working with an error something like this:

Unable to Establish a Wireless Data Connection.
Touch to Open APN Settings
Cause: UNKNOWN

The solution (in my case) was to create and use a new APN other than the default. To do this:

1. Go into Settings
2. Touch, More
3. Touch, Cellular networks
4. Touch, Access Point Names
5. You will likely see two existing APN’s in this list. Create a new APN for isp.telus.com. Yes, even if you already have one.

To creating a new APN click the + sign at the top, and the only two required field values you need are:

Name: It'll Work Meow (or whatever you want).
APN: isp.telus.com

Once that new APN is created, select it. You should be good to go.