Welcome to WebmasterWorld Guest from 188.8.131.52
The small trickle of traffic you are seeing - does it come from Google Search?
Did this site ever get the "google honeymoon"
I'm curious about where the "negligible" traffic is coming from.
Is the content still available on the original site and might be pulling traffic away from the new one?
What about the domain, was it parked before that?
BDW, you've left us with little to work with. Site is indexed. No obvious errors in delivery. No possible duplicate content. BTW, a downloadable PDF, unless walled off, can be indexed by the major SEs and thus "known".
I repeat: Could it quite possibly be there is no interest in the content?