This is from the department of "you asked for the partial material, and six months later won't respond, even to reject it." It came from an assistant to be fair, and yet no amount of cordial prodding of the Internet variety seems to work. Is this no news? Not long enough, yet? Or go screw yourself pilgrim? As always, thanks for the insight behind the curtain.
Unanwered emails from an assistant?
My first guess is that person doesn't work there anymore and the company server just eats the email instead of spitting it back out with an auto-reply of "sorry charlie".
If you really want to know if you're getting the brush off, phone and just ask the person who answers if "Sally Suds-Muffin" is still working there. 1:3 gets you a no.
If she does, write her off. That means keep querying as though it's a no. It may not be, but this isn't the time to bet the farm, or even a thin dime on her calling up and saying "whoa baby, this is the next DaVinci Code". Besides, do you REALLY want to work with someone who thinks ignoring email is acceptable?