Thanks for reply

It is working in some cases.
I have an an application where are open two databases at the same time (one is a common database -this is open always; and the other is a project database a user can choose what he needs). When the system starts the user is choosing one of the project database. So if I want to validate the common database I can open exclusively and this is working, if I choose an another project database (not that one what I choosed already at system startup) it is working fine, but if I want to validate the database what I choose at the system startup I can not open exclusively. I do not know what can be the problem.
The procedures are the follows:
I start the form where the user can select the databases and the tables from a menu procedure. I created a public variable to store the selected databases, tables etc. I release the form and in a function I have the real code.

here is the code what I use
if tlValidDatabase
if tcSelectDatabase = "DATA\COMMON.DBC"
close databases all
open database data\common excl
validate database
wait get_text("any_key") timeout 5
else
close databases all
open database &pcSelectDatabase excl
HERE IS THE PROBLEM IF PCSELECTDATABASE IS THE SAME WHAT I OPENED AT SYSTEM STARTUP
validate database
wait get_text("any_key") timeout 5
endif
close databases all
open database data\common
lcDatabase=goprogram.cDatabase
open database &lcDatabase
set database to &lcDatabase
endif

I hope you can understand my english and you can help me!!

Thanks
Iván