[Uninitiated]

Very specific problem with my Airport Express. Have searched through this forum and read up on all the kb articles I can find. But I cannot get my AE to connect to my ISP with an ADSL modem.
I've done hard and soft resets of AE unit. Reset and recycled power on my ADSL unit.
Using the airport assistant, I set up a new network, setting AE to connect by PPPoE and use DCHP to assign IP addresses on my network, following apple's knowledge base instructions. I have chosen "configure using DHCP" on my Powerbook's network settings, and deselected "connect using PPPoE." The light on my AE unit turns solid green. But the system gets locked into a never-ending "Looking for PPPoE host" and fails to connect. My PB system tells me I'm connected with a 10.0.x.x IP address, but when I go to the airport admin utility I find that it has received no IP address from the ISP.
If I connect using an ethernet cable, I have no problem. So it doesn't seem to be the ADSL modem, password or my PB's ability to configure with my ISP directly. Something is wrong with getting the AE to communicate with the modem or the ISP. Anyone have any ideas? The AE unit worked when I first got it last summer but it stopped working after a firmware update in October. Despite attempts to contact Apple support I can't solve the problem. Thanks for any help.

[Uninitiated]

Update: Reverting to firmware 6.1.1 resolved the problem. If anyone else finds themselves with a similar problem, try that.