I am afraid you did not include the registry.H file.
In your pogram do you have #include statement? Like:

#include registry.H


>I have included the Registry.PRG that is included into VFP package into my program: to access the registrykey
>This is the following code i am using: i am getting the error at the HKEY_LOCAL_MACHINE
>********************************************************************
>SET PROCEDURE to "programs\registry.prg"
>
>clear
>oRegistry=CREATE("Registry")
>
>*** Now Read the value for key sessionfinished
>
>? oRegistry.ReadRegistryString(HKEY_LOCAL_MACHINE,;
> "SOFTWARE\JUNGCLAUS SOFTWARE ENGINEERING\TWAINCommander",;
> "SessionFinished")
>********************************************************************
>
>Yuri,
>Can you please tell me what do i need to change to access the registry by using the registry.prg.
>
>Please let me know, since i need to deliver the project by friday.
>
>Thank you very much.