$My_Value = 'SuperUser'; # assumption for this exercise

foreach $item (keys %Myhash){ 
# $item = 'SuperUser' first pass through
    if ($item eq $My_Value)	{
	foreach $iteminitem (sort(keys %{$Myhash{'SuperUser'}})){
# $iteminitem = 'Username' first pass through
            foreach $iteminitem1 (sort(keys %{$Myhash{'SuperUser'}{'Username'}})){
## Here's the problem: $Myhash{'SuperUser'}{'Username'} = 2
		if ($iteminitem1 eq 'name' &&  $user_number == $Myhash{$item}{$iteminitem}{$iteminitem1}) {
		my $User = $iteminitem; 
			  }
			}
		  }
	    }
	 }

##</code><code>##

if (ref $iteminitem eq 'HASH') {
    foreach $iteminitem1 (sort(keys %{$Myhash{$item}{$iteminitem}})){
....
    }
}