Right. You can't use a network share as a "local destination" but running Crashplan on the machine effectively can get the data on that other machine...
I think you're making assumptions about the network destination.
...which I presume is the intention rather that specifically on a network share.
A network share is exactly what he laid out in his requirements.
Backups will be going to a network share
It sounds like you're assuming that the backup destination for these files will be another computer on the network. Yes, if that were the case then Crashplan could do this easily, and could even do it for free (you can back up two computers to each other without signing up for Crashplan's cloud services - local backups are also free).
Given the absence of information about the destination for these backups, I suppose I also made an assumption in guessing that the share was more of a NAS device than another computer. If that is the case, then unless there's been a Crashplan package written for that device
and that device runs Java, then Crashplan isn't going to back that device up, and Crashplan on the Windows 7 box can't reliably back up to that NAS device.
So I guess the question is: Tom, what are you backing up to?