Thermal conductivity script problem

Dear all, I was using the thermal conductivity script written by Reinier and I faced a problem. 
"Unable to copy a document into itself (function/property "CopyFrom") at -e line 296."

It may be because the input file is in .xtd format.I know the access documents should be .xsd format, but I don't know how to change it.What should I do?

Thanks in advance.