Well, I believe I have the initial HW version, with firmware 1.21. My router is also DLink, the older 614+ (which only had wireless b, thus the upgrade to the 1522 in order to get wireless N). The 1522 is hardwired by CAT6 to the 614+, though also routed through an additional Belkin switch. My Pio 1020 is also connected to the switch via CAT6, so it is not even connected to the 1522, but still drops network connection every 15 - 30 minutes if the 1522 is powered up.
My devices have reserved addresses via the 614+. I'm using mixed G and N mode wireless, though the Pio 1020 is not using wireless at all. Using WPA2/AES on the 1522.
I don't think the cable modem (my own MOTO 6120 via Comcast) has a thing to do with this problem, as it clearly is related to the 1522.