Could not load file or assembly

Hi All,
Hope you are doing good.
I am running on Visual Studio Ultimate 2013 update 4 and trying to compile DLL which has already been created in visual studio 2005.  Compile time I receive below exception.
Could not load file or assembly 'WorkflowGen.My, Version=2.2.0.0, Culture=neutral, PublicKeyToken=df70d2b8f21e0354' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
Appreciate your quick help.
Thanks in advance.