MN 700 interrupts downloads through MN 1000 DSL modem

Large downloads appear to be interrupted after a minute
or so after I installed an MN 700 router. Downloads were
fine with just the MN 1000 DSL modem connected through
MSN.

Downloaded the firmware, etc.upgrades (auto update says
all is current).

Have removed the MN 700 and all is fine again.
Reinstalling brings the problem back. Have tried
different channels for the wireless and other variables
inn the Base Station Management Tool.

Any ideas. Thanks - Ian B.