We have cisco aironet 1240ag series access points with system software filename c1240-k9w7-tar.124-10b.ja and system software version 12.4(10b)ja

We are experiencing problems with psion teklogix workabout pro pda who constantly are having problems connecting to the access point. Often they don’t get connected, sometimes they do and work for a few minutes and then don’t work again. The message we get in the log of the device =

-          Failed to associate with the ap

-          Preferred list exhausted

The message we get at the access point =

-          Interface Dot11Radio0, Deauthenticating Station 0016.e3da.d15b Reason: Previous authentication no longer valid

-          Packet to client 0016.e3da.d15b reached max retries, removing the client

We are at a loss because we cannot find any logic in the way it happens. We have 8 pda’s and only 3 have the problem. We also changed the network card in 2 of them without any success. We also reinstalled them without success. The problem started after we changed the ap earlier this year so we think it might be the ap. Maybe I can try a firmware update, but can you tell me which is the correct firmware for this device because I find several files on the webpage.

Thank you

Bellen kurt