Why This code doesn't work? FoxPro gaves an error.

In the Form I have a property:
.MyProperty="customers" &&Table Name

In a control InterActiveChange Event:
Private lcValue
lcValue=&ThisForm.MyProperty..firstname

This one works fine:

In the Form I have a property:
.MyProperty="customers" &&Table Name

In a control InterActiveChange Event
Private lcValue,lcTable
lcTable=ThisForm.MyProperty
lcValue=&lcTable..firstname

What's the difference?