while i try to run (F9) an executable OllyDbg displays the follow message:
inexact floating-point Use Shift + F7/F8/F9 to pass exception to program.
What can i do???
Thanks.

You usually can press Shift +F9 to bypass the exception.

unfortunately even if i press Shift + F7 or F8 or F9 OllyDbg doesn't work equally.
Excuse me, i took it for granted that i had already pressed keys SHIFT + ..
Indeed I will say you more; when I press the aforesaid key, it is like if it made a loop of operations, and the message is always the same one.
i thank you for whichever useful information about it.

you are probably working with a vb executable and you may have set a breakpoint in some place which it doesnt like so the seh trips in and produces the message
and without passing the exception to the handler it will keep on poppping up as many times as it errs
to pass the exception to the handler once olly pops it for the first time
go to debugging options (ctrl+o) --->exceptions-->add last exception-->press ok and check mark the ignore following exceptions checkbox
after that press shift +f9 if the exception is raised again olly wont pop up the message but will automatically pass the exception to the handler

but this wont guarentee that your app will run coz the next exception may well be cannot process exception and exit
to understand how seh works you need to find some tutorials on net
jeremy gordons tut comes to mind first there are others such as owl,comrade,rose,elicz,mattpietreks tuts on seh search for them and read them before you proceed
good luck

oh me anon you are great!!!!
thanks to your precious advice now it works very well.