Hi Jonathan. Thanks for sharing the XLSForm. It is always useful to dig into the problem. Rows 35 and 48 in your survey worksheet have exactly the same value in the name column. This causes an error when publishing the survey because a table cannot have two fields with the same name.
Typically, when you type two questions with the same name you will see them highlighted in red indicating that they are repeated. For some reason that escapes me, the yearssinceburnt duplicate is not being highlighted.
Renaming either row 35 or 48 will do the trick. Now, because Connect failed to publish it is most likely that you have a folder in ArcGIS Online as a left over and Connect will fail when you try to publish again. I suggest that after renaming the question, and before you attempt to publish, you go into your ArcGIS Online and completely delete the survey's folder in your Content tab.