You have a typo somewhere in user.config or web.config. probably a funky comment tag or a stray angle bracket somewhere.
Be careful with comments, if you have comment syntax with other comments inside it it will cause errors like this.
ie something like this:
<!-- this is a comment
<!-- and this is a comment -->
more commented stuff -->
will cause an error like this.
You can't go by the line numbers because when using a user.config file in addition to web.config it throws off the line numbering when the appsettings from user.config are combined with those in web.config, its treated all as one file by the parser so it sees different line numbers than people see when browsing the files.