Hardware question...

All right, here's my irritating issue:  My setup is Keyboard -> 16'
active USB extension cable -> KVM switch -> computer.  A cheap
keyboard I have (Asus ultra-thin) works fine, but my nice one (Das
Keyboard) does not.  The nice keyboard does work if connected directly
to the computer, connected directly to the KVM switch, connected to
the computer through the extension cable by bypassing the KVM switch,
connected to the computer through other (shorter) extension cables.
There are three LEDs on the nice keyboard (numlock, capslock,
scrolllock).  When in a working configuration, just numlock is lit.
When in the non-working config, all three are lit.  Non-working means
typing results in no output on the screen.  I should note that the
nice keyboard has a USB hub built in, but I don't need that to
actually work - just typing.  If I connect the nice keyboard to the
computer (without the KVM switch) through four short (about 3') USB
extension cables, it works fine, but if I add a fifth one I get the
same all-lights, no-output behavior as with the 16' plus the KVM
switch.  What would you suggest I do to make it work from 16' away
through the KVM switch?  I have tried putting powered USB hubs in at
various places without success.

 - Tony Yarusso