You certainly should be able to get it working without what I'm going to say next, and I hope that someone else can help you with that.

However, for the cost of a very inexpensive DSL/cable router (as low as $10 U.S. here in the states), you can completely avoid this problem and have an extra level of security as well. The router gets configured with your DSL login information and takes care of that, PPPoE and/or anything else that your DSL connection needs. You computer or computers run any OS you want and get their network setup by DHCP and you're on the network as soon as you boot. Keep your eyes open for a sale or a good price on one and I doubt if you'll regret it. I particularly like the features of the Dlink brand, but Linksys and others will work as well. Low end (best to avoid) are Belkin and Netgear (IMHO).