Problem fixed...
It turns out that the embedded page hyperlinks to the PDFs that I was attempting to index were invalid. However, ever browser known to man seemed to compensate for the invalid path, so I never picked up the error (until now).
The phpDig crawler didn't compensate for the error (No surprise really).
The incorrect relative path from the root level was:
../content/docs/newsletter/newsletter501.pdf
The relative path from the root level should have been either:
./content/docs/newsletter/newsletter501.pdf
or
content/docs/newsletter/newsletter501.pdf
Thanks for your help. Now on to MS Word Documents.....
