Pin outs are the same, but the cradle does provide power in addition to signals. I doubt you got two bad cradles. Have you tried the cradle in a different USB port? Also, the power connects on the cradle with the ax not fully seated, but data doesn't flow until it is all the way down. On my new cradle it was pretty stiff to get it fully seated. There is almost no room under the Ax once seated.
lbell, MikeC assumed you used the cable and cradle in the same USB port. Is that true? USB ports vary widely.
rittervonali, also try different USB ports.
Let us know what happens.
One final thing for both. Try running
resync between connections, particularly if the first one fails. Sometimes activesync needs to be restarted on the desktop to connect, and resync just stops and restarts it cleanly.