When I first got my La Fonera router I ran into some problems. First, when I tried to flash it, it said that Redboot for telnet was not enabled. What you have to do then is the following:
FIRST A VERY IMPORTANT NOTE: DO NOT PLUG THE FONERA INTO THE INTERNET. THE EARTH WILL EXPLODE. AND THE FONERAS FIRMWARE WILL BE UPDATED.
1. Check your firmware: Is it 0.7.1 r1 or lower? You are good to go. Is it higher (as in my case) than just grab a paperclip and hit the resetbutton for 20 seconds. Then wait till he comes back up.
2. Download this package (http://www.multiupload.com/75FEX6SAR8) MD5: 3cc427e39112fe2319009ae0e420efdd
3. Follow steps 1 trough 10 on this page: http://forums.hak5.org/index.php?showtopic=9908
(all the files that you need are in the zip. WinSCP and Putty are on the internet. Mr. Google can help you find them)
If you have questions. Just ask!