64bit - Could not load file or assembly 'ChilkatDotNet4' or one of its dependencies. An attempt was made to load a program with an incorrect format.

In a web application, the following error shows up when browsing to a page that instantiates a Chilkat object. Could not load file or assembly 'ChilkatDotNet4' or one of its dependencies. An attempt was made to load a program with an incorrect format.

code behind : protected void Page_Load(object sender, EventArgs e) { Chilkat.Crypt2 c = new Chilkat.Crypt2(); }

Windows7 64bit / VS2010 v10.0.30319.1 / ASP.Net v4.0.30319.272

Thanks