Have you tried opening the XML file in an XML editor, or an XML aware text editor like Notepad++?
On my thread about a similar problem in Ss2, I discovered that the FWD (survey) file contained extended characters - non-ascii and depending upon the version of InRoads, when the XML report was creqated, the extended characters were left alone - no error generated, or converted to ASCII - error message generated.
The reason the ASCII conversion generated the error was that one of the extended characters was a special double quote. If the value in the FWD was a regular quote, it converts in XML to " since a double quote is a reserved character in XML. But when the special quote was converted to a regular quote, it bypassed the code that should convert it to "e; which resulted in a stray double quote in the XML file. And in the world of XML, an error like that makes the entire XML file invalid.
I was able to use some of the tools in Notepad++ to manipulate the XML file to where its XML error checking code could report on a meaningful line number which eventually lead me to the stray double quote.
So, download Notepad++ and install it and enable its plugin manager. Then use it to locate and install the XML tools plugin. Use it to open an XML file that generates the error in the Report Browser and run the XML tools syntax checker and see if it reports an error. If it does, post your XML file and I will see if I can find the issue.