Teambuild not copying XAP fiesl to _PublishedWebsites

I have a TFS build for sivelright and it copies all the files in the web project to _PublishedWebsites, except the xap file. Error is

Web.csproj error MSB3021: Unable to copy file "Some.xap" to "c:\somewhere\Some.xap" Cou开发者_开发知识库ld not find file "Some.xap".

What it is trying to do, from where it is trying to copy and why it is failing?

Make sure your projects are built in the right order in your TFS Build Definition (Build Definition, Process, Required, Project to Build).