Wireless connection tend to be unreliable at time. Just recently I've been having trouble with my wireless connection disconnecting, later found out a neighbor was running on the same channel and it was interfering so I just switch it over to another channel and it seems to be OK.
Anything like cordless phone or Bluetooth devices that run on the same frequency as 802.11b and g can and will interfere with your wireless connection. Distance is also a factor.