If you're referring to either of these:
{INCLUDETEXT "C:\\Users\\Genius\\Desktop\\Text1.docx" "{DOCPROPERTY BkMk}"}
{INCLUDETEXT "C:\\Users\\Genius\\Desktop\\Text{DOCPROPERTY DocID}.docx"}
then:
1. The field brace pairs (ie '{ }') are all created in the document itself, via Ctrl-F9 (Cmd-F9 on a Mac); you can't simply type them or copy & paste them from a post.
2. Your document would need the Custom Document Property named BkMk or DocID, as appropriate, to exist and have a valid value.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]