"could not load file or assembly..." with sagepay dotnet integration kit

I've got the kit project working, but want to integrate it into my own web project. I used "add reference" on the project and located the "SagePay.IntegrationKit.DotNet.dll" file and added it. I was then able to reference the methods of the kit but when I come to build the project, I get:

Error   1743    Could not load file or assembly 'file:///C:\Users\localdev\Documents\Visual Studio 2013\Projects\myTest\myTest.Payment\bin\SagePay.IntegrationKit.DotNet.dll' or one of its dependencies. Operation is not supported. (Exception from HRESULT: 0x80131515)  

Am I doing this the wrong way? Am I missing something?

Found the solution on another stackoverflow question: 8524423

Just opening the file properties in windows explorer and clicking on 'Unblock this file' should also solve the problem