Lab 3b

I have a mac and followed the instructions using the plain text and matched the required preferences etc (step 107-112). I used the HTML - https://webto.salesforce.com/servlet/servlet.WebToLead?encoding=UTF-8" method="POST and followed the rest exactly. However on step 130 when I click the the file I created on my desktop I do not get the same outcome shown in the picture on the instructions and instead get this HTML. I don't know how to fix this and can't proceed without it.