Ask Netgear if there is new firmware but beware that most of these models are for use in home situations where you see less than 10 machines. I bet someone may tell you it's time to move up to office or commercial grade gear.
As to what's amiss, I agree it sounds like a bug but since it's not open source all you can do is reboot the router if Netgear does not have a fix.
I have a comcast cable modem internet access in the office and connected to it a Netgear router WNR3500L, then the router has DHCP enable to assign ip address to all the computers connected and of course the router also connect to a switch where actually i have about 50 computers connected, by the way i am not using this router as wireless since i use around the company wireless access point to allow laptops to connect, the problem is that after a few days working the router start dropping off some computers (this mean some computer are getting ip address and others are not able to get an ip, my ip range is as this 192.168.0.xxx, ok i have the router setup in such way that the first ip to asssign should start as 192.168.0.111 and allow up to 120 more to be assigned so the last ip should be then 192.168.0.231, ok so also at night when no one is working in the company i make backups thru the internet so the router is in use over night to send information to a computer that is outside of our office, i just wondering if anyone can help on this why it is not assigning ip or allowing some users in the morning to connect, by the way i do not use my server to use DHCP SERVER(cause i cannot) so the router assign ip to the computers and also allow them to connect to the internet, Do you think it is that the router does not release the overload bandwith and in the morning it is not strong enough to accept request from the computers ? please i need some help here , or if anyone knows of a router that can work with comcast cable and do not produce this issue Thanks a lot