cnPilot E410 losing LAN connection

Hi, I have about 40 cnPilot E410 devices on my network and for some reason 37 of them lost LAN connection about a month ago but the wireless side stayed on I had to go by and rebooted them all. They all came back up after the reboot. It seems to become a regular thing even after updating to the latest firmware . Can anyone give me ideas or suggestions on preventing this.

Thanks in advance

You should probably post this in the forum section under cnPilot. You are more like to get a response.