This applies to WorkflowGen version 5.x.
WorkflowGen Windows Service running with an Oracle database triggers the following error message:
Attempt to load Oracle client libraries threw BadImageFormatException.
This problem will occur when running in 64-bit mode with the 32-bit Oracle client components installed.
As indicated in the error message, your WorkflowGen Windows services are running in 64 bit and tries to load a 32 bit Oracle client components.
Install the 64 bit Oracle client provider to replace the 32 bit version.
Force the WFG services to run in 32 bit using the CorFlags Conversion
Additionally, you have to make sure the COM+ are installed and registered properly when migrating to a 64 bit machine.