I also get this problem.
Running Fedora Core 10s latest kernel och associated stuff.
I temporary solve this problem by restarting NetworkManager.
I've also noticed that this problem seems to occur more often when downloading at greater speeds.
I have yet to encounter this problem when just casually browsing the web.
Linux 22.214.171.124-117.fc10.x86_64 #1 SMP Tue Nov 18 11:58:53 EST 2008 x86_64 x86_64 x86_64 GNU/Linux
$ cat /sys/module/rt2x00*/version
I suppose you could temporary "fix" this by something like..
ERROR=`tail -5 /var/log/messages|grep "Arrived at non-free entry"`
while [ "$ERROR" == "" ]
echo "No error"
echo "Error found: $ERROR"
sudo service NetworkManager restart