System.Bad Image Format Exception Could not load file or assembly “Interop.iwwfeaLib”

Symptom

You may receive the exception text “System.BadImageFormatException” in the component “iwwfeaLib”

Cause

Caused by loading the 64 bit workflow components into a 32 bit web application pool.

Resolution

Within IIS 7 under the Advanced properties for the application pool that workflow is running under, ensure the the ‘Enable 32-bit Applications’ property set to ‘False’.