Rick: thanks for your advice. I am sorry to take more of your time, just one more question : I got an e-mail from Seaith Jacobs that suggest the following:

"First, if you haven't done so already, I suggest installing SP4 and using the Session class (part of VFP6 starting with SP3). By default, these classes are private data sessions. If you are using the Custom class (actually, any class but Form [setting the datasession to private] or Session), then all instances are in the global datasession."

Do you think is a goood idea to use the Session Class ?