Validation Errors - what do teh columns and lines refer too

i am loving your service - I have learned a ton.  One thing that seems
super basic, but I haven't been able to figure out in the FAQ and mailing
list archieve is what the columns and lines reported with each error mean.

I am working off a word press template and don't see columns or lines
listed anywhere.

Sorry if this is a super elementary question - trying to get my site
cleaned up.

Site - http://www.forensiccrimescene.com/

Example - Line 85, Column 8: document type does not allow element "br"
here; assuming missing "li" start-tag

This seems like it would be easy to fix if I knew where to go to fix it.

Thanks for your help!

KT. B