you are using $Mwnd 0 when you almost certainly mean $Mwnd[0]

This is just an artifact of PerlMonks turning things in brackets like [0] into links (when the brackets are found outside of <code> tags, and aren't HTML-escaped, of course).  If you click on the xml link at the top of the node, you'll see that the brackets are in fact there in the original input.

(In cases of misformatted nodes, I usually just cut-n-paste the respective section out of that XML doctext from the browser into my editor. This way I also get the original linebreaks, without the need for manual reformatting. — But this is not meant as an invitation for people to no longer care about proper formatting/tagging... Please!! ;)