MacBook Pro won't find network boot disk

My optical drive doesn't work on my MacBook Pro, and my Internet connection is too slow to use the recovery partition to download Lion. I have a disk and a Windows PC I can use on the same network. I installed the disk sharing software from Apple on the PC, and used the remote install program that comes on the disc. I hold down Option ⌥ when booting up my MacBook. It is plugged in via Ethernet to the same network, but the network disk never appears. If I press N then the network icon appears, pulsing, but it never finds the Windows shared disk. What am I doing wrong? Will this work better if plug the Ethernet cable directly from the PC to the Mac, skipping over the network?