Solid does not Regenerate using VB API

Using VB API with Creo 5 and as mentioned in the help file, I have set the configuration option regen_failure_handling to resolve_mode in the Creo Parametric session.

Even after that solid.Regenerate(Nothing) does not regenerate the model.

[EDIT]: Subsequently I created an object of type CpfcRegenInstructions and passed it to the Regenerate method as an argument, but the following line says "Class not registered":

Dim creoRegenIns As CpfcRegenInstructions = New CpfcRegenInstructions

ForceRegen, RefreshModelTree, UpdateInstances, and AllowFixUI are all set to True.

Is there any solution to this?

Thank you.

~Tushar