As well, unless I am reading the post wrong, it sounds like you are configuring the empeg with a specific IP address to connect to your works' network running on a DHCP server? Is this right? If it is, read below -- if not, well then just ignore me...

If so, the solution is pretty simple -- when you are going to use the empeg at work, just set it up for DHCP and you should be fine. What you are doing is telling the dhcp server to use a specific IP, which 1)Might be in use on another computer already, or 2)THe DHCP server does not like machines to pick their own static ip.