ping error 1231

Hi,

I'm setting up a wireless camera on an Unmanned Aerial Vehicle (UAV)
and need an ad-hoc network, this is because i have powerful amplifiers
at my pc and on the aircraft. A normal wireless network needing a
router would not have sufficient transmission range, as the router
signal would be a weak link in the chain.

Strangely, I can only access the camera over the ad-hoc network for
about 30 seconds, then the connection breaks down. Everything works
fine when connevcted through the router.

Trying to ping the camera's IP, I get "transmit failed, error code
1231"

Not quite sure what in earth to do. Please help!

Adam