Can you ping the server from either the WinPE or the PCDOS boot key? What network protocols does your server offer, and is this a first time ever installation for you, or did you have a previous Ghost server up and running?
The most common reason for the problems you are experiencing is a failure for the NIC drivers to load correctly on the machine being imaged. When you use DHCP then it it pretty obvious as the IP address defaults to 127.0.0.0 if there is no connection, but with static IP addressing, I believe the IP address can get assigned even if one "layer" of the network stack has not loaded properly.
With WinPE, bear in mind that you need to add NIC drivers for Vista 32 bit edition, as WinPE V2 is based on the Vista kernel. This is a requirement regardless of what operating system you are imaging. However, some modern machines do not offer Vista drivers, so you may need to look at creating a WinPE V3.1 environment based on the Win 7 kernel and use Win 7 drivers. Terry Bu has written a nice article about how to do this:
https://www-secure.symantec.com/connect/articles/creating-and-using-winpe31-image-gss-251
and a second article, which he will no doubt post the URL to, adds further information about fooling the Ghost environment with the newer drivers.