I don't remember the ERPC bit, but I don't think it was that long ago, 6 months max, might be worth a search?
Glaskham, with DS2 I didn't get a BFP till I was 9 days late, and others have been 4,5,6, weeks+ before they get a BFP, and some (I think Kay's firend or somesuch) never got one throughout the whole pregnancy!
It seems that some women just don't process the hCG into the urine for a while, or ever!