I recommend doing this as I do with my printer and other devices that don't need a IP address reservation, set a static IP address ON the printer. Set it to 192.168.0.98, 98 being the first 2 digits in the printers model number and it's out side of the DHCP reservation pool.
You can do this for those devices that don't need a lot of router management or Internet access, Devices like NAS, printers, Fax, phones and house devices and such. I do this for a several of my devices. This will free up the reservation pool for other higher priority devices that need router management.
Try this first and if it doesn't' seem to clear the problem, your 2 versions of FW behind, you could update FW then test again.
If you do choose to update, please follow this always:
FW Update ProcessYou can get FW here:
http://forums.dlink.com/index.php?topic=59583.0