System.IO.FileLoadException occurred in unknown module in MFC project using a WPF user control

I have a project in MFC that uses a WPF user control targeting .NET 4.0. When I run the program I get the following exception

An unhandled exception of type 'System.IO.FileLoadException' occurred in Unknown Module.

Additional information: Could not load file or assembly 'MyProject' , Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. Could not find or load a type. (Exception from HRESULT: 0x80131522)

When I break the execution, It shows following module information

Version: 6.3.9600.16384 (winblue_rtm.130821-1623)
Original Location: C:\Windows\SysWOW64\ntdll.dll

I tried single stepping from the begining, but the first time I hit F10 I get this exception. Can anyone please explain to me this exception/issue?