Your being too literal.
Why would a property be there in dev mode but not at runtime?
has that ever happened to you?

>I have class called "MyClass". It has two properties, "Foo" defined as string and "Foo1" defined as a numeric (o mage to Calvin Hsia).
>When i execute my app in dev mode and step through the code where these properties are assigned values:
>Foo = ""
>Foo1 = 0.00
>life is good.
>
>Next i run the app without debugging assuming the best and these property assignments are made without issue.
>
>Now i am ready to execute my app in run time and my code fails at this line:
>Foo1 = 0.00
>The error is: "Property "Foo1 is not found."
>
>VFP 8 by the way.
>
>Any clues?

Foo =  ""
Foo1 = 0.00

This is not a property assignment. You are assigning values to memory variables.

Foo1 = 0.00 

giving an error about property is nonsense, again it is not a property assignment but a memory variable. Are you sure those don't have a . (dot) prefix and included inside a with ... endwith block?