1. Word is not a good option for text editor which is what you need for clean XML.
Dreamweaver does XML beautifully. But if you mean the person giving you content doesn't have Dreamweaver they have other no cost options. I'd recommend some of the free text editors out there. On Windows platforms, Notepad utility will work in a pinch. If they are on a Mac, the free Textwrangler from Barebones would work wonders as well. They should be able to open your Dreamweaver-created template, copy their content blocks from Word, paste into the proper tag wrapper in the open template (in TextWrangler or Notepad) and save that notepad/textwrangler file as is. Save your template as .xml, and hopefully with one of the mentioned apps they can keep it in that format ".xml"
2. It is possible they will STILL import unwanted wild characters that throw off your XML, even copying into TextWrangler and Notepad, but you'll need to look in Dreamweaver to hopefully spot these hidden characters and deal with them on an individual basis. Some special characters like tabs, line breaks, register marks, trademarks, copyright symbols, etc., will need to be substituted for the proper chaacter code equivelant if Indesign throws up an error on importing the XML. I have a few here:
® (registered mark)= ®
™ (trademark)= ™
(LINE BREAK) =
© (copyright)= ©
3. I think maybe there is some additional required document structure for your XML to work well with Indesign:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
Note that the path to the image file has to be relative to where the XML document is living at the time it is imported into Indesign (or else an absolute path, like an HTTP URL).