pdf not accessible <cfpdfform>

I am trying to write a Flex app to launch a PDF.

The Flex app is able to grab data from the database ok.... however when I click a button on the Flex app to invoke a CFC to invoke <cfpdffrom>... an error message indicates...

     Unable to invoke CFC - the pdf file specified in the cfpdfform tag either does not exist or is not accessible by this tag.

When I change the path to the pdf, each subsequent error message shows the correct path to the pdf.  Thus, the path seems to be ok.

I am able to launch the pdf ok via a .cfm

Help would be appreciated.

--Bill