I haven't tested your code, but I doubt you really want 1 .. 300 for the columns. This would be more appropriate:

foreach my $col ( 'A' .. 'XFD' ) # Assuming >= Office 2007
{
    foreach my $row ( 1 .. 300)
    {
        next unless defined $Sheet->Cells("$col$row")->{Value};

        # the rest of your code here
    }
}
[download]