The term 'Network Locked" usually means the SIM belongs to a carrier other than that of the phone. For example a Rogers SIM in a Telus phone.
It is possible you have a malfunctioning SIM - it does occur. Possibly you can return to the location where you purchased the SIM and have it assessed or replaced.
Have you tried calling Telus? That would usually be one of the things to try for something like this. It is possible the SIM may be defective or there may have been a problem with activation. Also double check that 3G is enabled on the phone. If it was turned off in the settings by accident, that can cause the phone to fail to connect.
Either try it with online chat then or borrow a phone. The forums are a place to share and exchange ideas but have absolutely zero connection to user accounts. You'll need to speak with Telus one way or another if the issue is activation related.