Hey Bizzy, I have an idea:
it would be cool if you made it similar to the debugger in software development kits - you'd put a large memo component under the edit box (used for browsing I think) where the code of the xml file would appear. Then if the debugger found some imperfection in the xml, the user would just double click the line with the error description and in the memo the cursor will jump straight into the line where the error was found.
Include a 'Save' button, so that the user would be able to save the editted file directly from this utility.
Just a few thoughts, good luck with further development