I bought a Linksys range extender RE1000, a decision that I regret. The first issue I ran into is that it has the same factory set IP address as my Linksys modem-router WAG200G, so trying the automatic setup using wifi ran into some conflicts immediately, and I had to proceed by connecting the RE to my computer by cable and enter all settings manually. I tested it without any wifi security enabled, and it worked. Then I set wifi security to WAP2 mixed and immediately lost the signal.
Next came a few hours of trying to figure it out myself and then some more hours with the Linksys web support people, who finally acknowledged that the RE1000 would not work using certain wifi security settings.
The local shop where I purchased the RE1000, tested it with some other routers, and it worked fine, but confirmed that it did not work with the WAG200G. They even sent a technician out to try and get it set up, but the guy also failed. Unfortunately, they took the position that since the device worked with other routers, it was not faulty enough for a refund, and they actually suggested that I get another router. So I got no solution there.
After some correspondence with Linksys, they finally wrote me that they would refund the purchase price. They got my account details, but a couple of weeks later went back on that decision and now say that my case is pending with the final decision making authority (they seem to be a bit disorganized, to put it nicely). So, although Linksys itself confirmed the partial incompatibility of its two products, I am stuck with no solution.
Therefore, if you are thinking of purchasing anything from Linksys, you better get a warranty from the seller that in case you have any problems, you can return the device to him and do not have to deal with Linksys directly, because that is just a big time-wasting headache.
This is not a issue limited to linksys. Range extenders use a protcol called WDS but that is not really a standard so you get lots of incompatibility.
Most so called range extenders on the market are pieces of crap designed to be as cheap as possible. The only way a range extender will work well is if it contains 2 radios, one to talk to the main router and a second to talk the clients. Of course you need to run these on different channels.