I am running Ubuntu 12.04 on a dell inspiron desktop (core 2 duo) and am using wicd to manage my network/wifi.

I've found that the WiFi card in the machine has trouble staying connected to my router (I believe this is a function of distance between the two), so I've taken an old Belkin F5d7231 wireless router and installed dd-wrt on it to use as a wireless bridge hoping that it will have better reception. I think everything up through the wireless bridge is working OK since I have no problems accessing the internet through it with my MacBook.

The problem arises when I try to hook the ubuntu machine up to the wireless bridge. It will connect for a few minutes, but it will quickly disconnect without clear triggering event; it may be more likely to disconnect if there is a heavy traffic load going over it (could be something as simple as "cat big_text_file" in an ssh session). I've tried switching from dhclient to dhcpcd without much improvement.

Here is the output from the syslog when it connects:

Jun 30 17:10:08 Chicabuntu dhcpcd[28278]: wlan1: dhcpcd not running  
Jun 30 17:10:08 Chicabuntu dhcpcd[28278]: wlan1: exiting  
Jun 30 17:10:08 Chicabuntu dhcpcd[28312]: eth0: dhcpcd not running  
Jun 30 17:10:08 Chicabuntu dhcpcd[28312]: eth0: exiting  
Jun 30 17:10:08 Chicabuntu avahi-daemon[1041]: Interface eth0.IPv6 no longer relevant for mDNS.  
Jun 30 17:10:08 Chicabuntu avahi-daemon[1041]: Leaving mDNS multicast group on interface eth0.IPv6 with address fe80::21c:c4ff:fe31:1a83.  
Jun 30 17:10:08 Chicabuntu avahi-daemon[1041]: Withdrawing address record for fe80::21c:c4ff:fe31:1a83 on eth0.  
Jun 30 17:10:08 Chicabuntu kernel: [15184.976127] tg3 0000:3f:00.0: irq 44 for MSI/MSI-X  
Jun 30 17:10:08 Chicabuntu kernel: [15185.010805] ADDRCONF(NETDEV_UP): eth0: link is not ready  
Jun 30 17:10:08 Chicabuntu dhcpcd[28347]: eth0: dhcpcd not running  
Jun 30 17:10:08 Chicabuntu dhcpcd[28347]: eth0: exiting  
Jun 30 17:10:08 Chicabuntu kernel: [15185.180156] tg3 0000:3f:00.0: irq 44 for MSI/MSI-X  
Jun 30 17:10:08 Chicabuntu kernel: [15185.212785] ADDRCONF(NETDEV_UP): eth0: link is not ready  
Jun 30 17:10:10 Chicabuntu kernel: [15187.027445] tg3 0000:3f:00.0: eth0: Link is up at 100 Mbps, full duplex  
Jun 30 17:10:10 Chicabuntu kernel: [15187.027452] tg3 0000:3f:00.0: eth0: Flow control is on for TX and on for RX  
Jun 30 17:10:10 Chicabuntu kernel: [15187.028300] ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready  
Jun 30 17:10:10 Chicabuntu dhcpcd[28353]: eth0: dhcpcd 3.2.3 starting  
Jun 30 17:10:10 Chicabuntu dhcpcd[28353]: eth0: hardware address = 00:1c:c4:31:1a:83  
Jun 30 17:10:10 Chicabuntu dhcpcd[28353]: eth0: DUID = 00:01:00:01:17:81:85:79:00:1c:c4:31:1a:83  
Jun 30 17:10:10 Chicabuntu dhcpcd[28353]: eth0: broadcasting for a lease  
Jun 30 17:10:11 Chicabuntu avahi-daemon[1041]: Joining mDNS multicast group on interface eth0.IPv6 with address fe80::21c:c4ff:fe31:1a83.  
Jun 30 17:10:11 Chicabuntu avahi-daemon[1041]: New relevant interface eth0.IPv6 for mDNS.  
Jun 30 17:10:11 Chicabuntu avahi-daemon[1041]: Registering new address record for fe80::21c:c4ff:fe31:1a83 on eth0.*.  
Jun 30 17:10:20 Chicabuntu kernel: [15197.568016] eth0: no IPv6 routers present  
Jun 30 17:10:29 Chicabuntu dhcpcd[28353]: eth0: offered 192.168.1.111 from 192.168.1.254  
Jun 30 17:10:29 Chicabuntu dhcpcd[28353]: eth0: checking 192.168.1.111 is available on attached networks  
Jun 30 17:10:30 Chicabuntu dhcpcd[28353]: eth0: leased 192.168.1.111 for 86400 seconds  
Jun 30 17:10:30 Chicabuntu dhcpcd[28353]: eth0: adding IP address 192.168.1.111/24  
Jun 30 17:10:30 Chicabuntu avahi-daemon[1041]: Joining mDNS multicast group on interface eth0.IPv4 with address 192.168.1.111.  
Jun 30 17:10:30 Chicabuntu dhcpcd[28353]: eth0: adding default route via 192.168.1.254 metric 0  
Jun 30 17:10:30 Chicabuntu dhcpcd[28353]: eth0: exiting  
Jun 30 17:10:30 Chicabuntu avahi-daemon[1041]: New relevant interface eth0.IPv4 for mDNS. 
Jun 30 17:10:30 Chicabuntu avahi-daemon[1041]: Registering new address record for 192.168.1.111 on eth0.IPv4.  
Jun 30 17:10:30 Chicabuntu dhcpcd.sh: interface eth0 has been configured with new IP=192.168.1.111  
Jun 30 17:10:39 Chicabuntu ntpdate[28439]: adjust time server 91.189.94.4 offset 0.001915 sec  

And here is the syslog from when it shuts down the connection without reason:

Jun 30 17:12:15 Chicabuntu kernel: [15312.575455] tg3 0000:3f:00.0: eth0: Link is down  
Jun 30 17:12:16 Chicabuntu dhcpcd[28603]: eth0: sending signal 1 to pid 28361  
Jun 30 17:12:16 Chicabuntu dhcpcd[28361]: eth0: received SIGHUP, releasing lease  
Jun 30 17:12:16 Chicabuntu dhcpcd[28603]: eth0: exiting  
Jun 30 17:12:16 Chicabuntu avahi-daemon[1041]: Withdrawing address record for 192.168.1.111 on eth0.  
Jun 30 17:12:16 Chicabuntu avahi-daemon[1041]: Leaving mDNS multicast group on interface eth0.IPv4 with address 192.168.1.111.  
Jun 30 17:12:16 Chicabuntu avahi-daemon[1041]: Interface eth0.IPv4 no longer relevant for mDNS.  
Jun 30 17:12:16 Chicabuntu dhcpcd[28361]: eth0: removing default route via 192.168.1.254 metric 0  
Jun 30 17:12:16 Chicabuntu avahi-daemon[1041]: Interface eth0.IPv6 no longer relevant for mDNS.  
Jun 30 17:12:16 Chicabuntu avahi-daemon[1041]: Leaving mDNS multicast group on interface eth0.IPv6 with address fe80::21c:c4ff:fe31:1a83.  
Jun 30 17:12:16 Chicabuntu avahi-daemon[1041]: Withdrawing address record for fe80::21c:c4ff:fe31:1a83 on eth0.  
Jun 30 17:12:16 Chicabuntu dhcpcd[28361]: eth0: netlink: No such process  
Jun 30 17:12:16 Chicabuntu dhcpcd[28361]: eth0: removing IP address 192.168.1.111/24  
Jun 30 17:12:16 Chicabuntu dhcpcd[28361]: eth0: netlink: Cannot assign requested address  
Jun 30 17:12:16 Chicabuntu dhcpcd[28361]: eth0: exiting  
Jun 30 17:12:16 Chicabuntu dhcpcd.sh: interface eth0 has been brought down  
Jun 30 17:12:17 Chicabuntu kernel: [15313.612141] tg3 0000:3f:00.0: irq 44 for MSI/MSI-X  
Jun 30 17:12:17 Chicabuntu kernel: [15313.644703] ADDRCONF(NETDEV_UP): eth0: link is not ready  
Jun 30 17:12:17 Chicabuntu dhcpcd[28674]: wlan1: dhcpcd not running  
Jun 30 17:12:17 Chicabuntu dhcpcd[28674]: wlan1: exiting  
Jun 30 17:12:17 Chicabuntu dhcpcd[28708]: eth0: dhcpcd not running  
Jun 30 17:12:17 Chicabuntu dhcpcd[28708]: eth0: exiting  
Jun 30 17:12:17 Chicabuntu kernel: [15313.912147] tg3 0000:3f:00.0: irq 44 for MSI/MSI-X  
Jun 30 17:12:17 Chicabuntu kernel: [15313.944746] ADDRCONF(NETDEV_UP): eth0: link is not ready  
Jun 30 17:12:18 Chicabuntu kernel: [15315.592569] tg3 0000:3f:00.0: eth0: Link is up at 100 Mbps, full duplex  
Jun 30 17:12:18 Chicabuntu kernel: [15315.592576] tg3 0000:3f:00.0: eth0: Flow control is on for TX and on for RX  
Jun 30 17:12:18 Chicabuntu kernel: [15315.593399] ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready   
Jun 30 17:12:20 Chicabuntu avahi-daemon[1041]: Joining mDNS multicast group on interface eth0.IPv6 with address fe80::21c:c4ff:fe31:1a83.  
Jun 30 17:12:20 Chicabuntu avahi-daemon[1041]: New relevant interface eth0.IPv6 for mDNS.  
Jun 30 17:12:20 Chicabuntu avahi-daemon[1041]: Registering new address record for fe80::21c:c4ff:fe31:1a83 on eth0.*.  
Jun 30 17:12:29 Chicabuntu kernel: [15325.680019] eth0: no IPv6 routers present   

If this isn't useful, I can also post the wicd log, but that is kind of long. If anyone could help me I would be eternally grateful.