192.168.0.x is not manditory. I have my Beo6 working on a 10.0.1.x network.
I have a hard time believing this would be a dhcp issue. I mean, afaik, dhcp has been working pretty flawlessly for maybe 10 yrs or so (note the poster's comment that other cheap devices connect with no issue)... I have a hard time believing B&O would mess it up. I would imagine they're using some sort of standard library for their IP stack...
Then again, as Keith correctly suggests, enterprise routers can be configured in all sorts of ways not typically found in a home network. For example, maybe the DHCP server is not at x.x.x.1 which is the convension of all home network router's that I've seen (i.e. cisco/linksys, netgear and apple). I see no ability to manually enter a DHCP server IP in the Beo6 so perhaps this is the issue. To find the DHCP Server's IP drill into your computer's wireless network properties and look for an entry titled something like "IPv4 DHCP Server".
I would also not rule out that there's an issue with the wireless security (these standards have evolved over the years so, to me, this is much more likely area for problems). Look at the wireless network properties on a computer connected to this network and validate that they are using WPA security (I don't know if it matters if it is WPA/2-Personal/Enterprise - I'm currently successfully using WPA2-Personal). I don't know if the Beo6 supports other standards, but it definitely supports this one.
Stan