PropertyBag Error

I create a persistable class with attributes. One of these attributes is a collection of another persistable class.
I save my object with WriteProperty method, I close my application.
When I open again my application, I want to retrieve my object's informations, but ReadProperty method
provokes a run time error "713" with below message :"Class not registered. Looking for object with
CLSID : {.........}"

Could you explain me why I've got this error message and what can I do ?

Have you tried compiling your child class, It's just a guess but I think it'll work.

Quote:

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Have you tried compiling your child class, It's just a guess but I think it'll work.

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These classes (child and parent) are included in an only project, and I confirm, I compiled this project and these classes.
In error message, the CLSID is different for each execution like classe is created in dynamic mode.