Door sensors not working on my Veritas 8C!!?

I have a Veritas 8C fitted and my lovely husband accidently scraped the wire leading to my back door sensor and now it won't arm that zone, just making the tamper beeps. How do we fix it? Is it as simple as taping over the exposed wire?

Also, the sensor on my front door has just stopped working - do I just need to replace it? Desperate as both doors will not arm and I have 3 little ones and I use the chime devise. Hope this is enough info.

Help please x

Jo
November 2010