imobiliser or key problems

[sahk]

I have an N reg Audi A4 with about 100k on the clock. When i try to start the car the imobiliser light flashes and car cuts off.

Is this a big problem and how much would it cost to repair.

[MisterD]

Have you changed the dial pod? Instrument cluster and ECU are paired. Either that or your immob. has gone pop?