>Hi all, i have a problem with this form that find clients, when i clic the search button it shows the find window then if success shows the select window wich have a listbox then put the focus on it to show the selected client. When the user digit a inexistent client i show the find window again but, at the moment the form try to put the focus on the listbox shows the error "can't call setfocus from a valid event"
>how can i fix it? thanks....

Move your code to lostfocus. It's very dangerous to let the focus go on other objects while in a valid, that's why it doesn't let it and behaviour is different depending on version.
Cetin