Move code into master page it stops working

Hi,
Here is my scenario.  Some time ago I converted an old windows application to a web application.  This web application works fine as a stand alone app.  I was recently informed that my client had a new standard layout and they are using a master page.  They sent me the master page.
The web application is quite basic in that it makes a number of calls to a web service to retreive a list of customer, retrieve list of products and allows customer to create an order containing products.
I did the following to get make use of master page:
Copied it to my solution Update the page directive to include the MasterPageFile attribute and set it to point to master page Added the relevant content areas to my page Copied my code (control declarations etc) into the relevant content areas. The application compiles corr ...