Our WAP4410N also shipped with firmware version 220.127.116.11 and is experiencing most of the problems reported in these discussion threads. Keep in mind we have a very small branch office, and we use this as our only wireless AP. The configuration is very very basic.
When I first set it up performance was absolutely *horrible* (I was going to throw it out) until I tried setting the Channel Bandwidth to 40MHz which brought it to life, albeit with the occasional dropouts being reported here. Is this suppose to work at 20MHz? I don't really care really, but just surprised at the out-of-the-box experience.
Once I figured this out, the next issues was that it seems it to have a hard time keeping linked-up with a 1000M fixed switch port (not auto-negotating, fixed). If I set to 100M fixed then it goes a much longer period of time before dropping, but of course the performance is 10x slower (we do a lot of large file transfers), i.e. ~500Kbps vs. ~5Mbps. Oh well.
So it still drops out at least once a day. Sometimes unplugging/plugging the ethernet cord helps, other times a reboot is required. I also tried using a UPS to stabilize power but that didn't help, probably has nothing to do with it in my case. I also keep it very cool, no luck helping with dropouts. I tried resetting to factory defaults several times, no luck either. Tried turning off all secruity, etc., no luck.
The only thing I have not tried is re-flashing the firwmware, just don't believe that will help, unless someone here can tell me the online firwmware is actually different than the same version pre-installed.