print " FILEXML <Structures>";
#print "<?xml  version="1.0" encoding="ISO-8859-1"?>";

##</code><code>##

while( @data = $sth->fetchrow_array() ) 
{
    # I GENERATE THE STRUCTURE OF THE XML FILE
    print FILEXML "<Book>";
    print FILEXML "<Author>$data[0]</Author>";
    print FILEXML "<Title>$data[1]</Title>";
    ...
}