Problem finding a specialist font

I wonder if anyone can help.  I use PDFCreator from within the music score-writing package SIbelius - to print scores and parts.  It has always worked extremely well.

Unfortunately, I am now getting the following error

ERROR: undefinedresource

OFFENDING COMMAND: findresource

STACK:

/ADBCFF+OrsoText

/CIDFont

/ADBCFF+OrsoText

[0 -1000 350 0 ]

81

 

OrsoText is an open-type font supplied to me by a Music Publisher.  I have managed to print using this font before, and cannot imagine why not now.  I onl7y recently upgraded PDFCreator, so went back to Version 1.4.3 and tried again.  No luck - any help greatly appreciated.