ISP issues

Hello, all.

I'm trying to program a large number of 90S2313s, so
I knocked up a ZIF socket to a 6 pin header and put
in a little power supply.

I tested the wiring and it seems to be right, but
neither of the ISP capable programmers I have--
STK500 and an AVRisp--seems to want to touch it.
They read back the target voltage just fine, but
fail to go into program mode.

Is there anything special that needs to be in the
target for an ISP programmer to work?  Pullup 
resistors or anything?

I used a VOM to verify that my fixture matches
the connections in the STK500 on the Vcc, GND,
RESET, SCK, MISO, and MOSI pins.  Do I need anything
else?

Cheers,
David