Yes in theory that should work so long as you are not having issues with 2 people trying to write to the file at the same time. I really do not know a lot about the gotchas of XML I rarely use it in my projects and generally opt for a database or other file type rather than XML. I know a lot of people like to use XML and it is way overused in many cases. I have always saw it as a poor option especially in VB6. There is a lot of overhead with XML, a lot of extra data in the files and the VB6 support for it is less than ideal.

btw I have never been on a system that had a Z drive mapped. my systems here drive letters run C-M