Can't replace DBCS with SBCS font - error

Been working to track down a problem with symbols not displaying properly in
an engineer's Word document, from one computer to another.

This paper was emailed to my boss from one of his former grad students. The
original version received on his old computer displays the characters
properly.

Then we got him a new computer, and SOME of the symbols are no longer
displaying properly.

Have check to see that all fonts are the same on both computers. (They are)
Have checked Regional and Language Settings. (Same)

Have checked Tools / Options / Compatability / Font Substitutions - trying
to change the substition for the symbol font "SymbolMT" gives the error
"Can't replace DBCS with SBCS font"

I have Googled this phrase and find several discussions about it, but no
solution.

Any help is appreciated.

Thanks so much,

Debi