Well, clearly your application is loading the Jiwa 7.2.0 assemblies and not the Jiwa 7.2.1 assemblies.
Have a read of
How the Runtime Locates Assemblies.
Two things to note :
1) if you have a .config file for your .NET application you can change the binding behaviour - check and perhaps you might opt to create one to override the bindings
2) You can put Jiwa assemblies in the GAC as they are strongly named - if you've done this previously it will use those instead of assemblies in the same folder as your application