Larry,
I usually call my report forms from a method within my form.
In the method, i would initialize certain local variables and then call the report via report form xxx. But when the report's datasession is set to private, the error message "variable yyyy not found" would appear.
But when those variables are set to public, then I do not have the error.
But I prefer not to use public variables here as it could mess things up.
Yau