Quartus II 11.1sp2 programmer does not recognize EPC2LC20

Thanks to you both for the prompt responses! FYI I downloaded the version of the tool that the customer uses (8.1) and it doesn't perform any differently.

Here's a copy of the output from jtagconfig (talking to a single EPC2LC20 through a USB Blaster):

C:\altera\11.1sp2\qprogrammer\bin>jtagconfig --debug

1) USB-Blaster [USB-0]

020041F9 (IR=11)

Captured DR after reset = (0020041F9) [33]

Captured IR after reset = (2A9) [11]

Captured Bypass chain = (2) [2]

I connected the USB Blaster to another board design for which the Altera device can be programmed and here are the results:

C:\altera\11.1sp2\qprogrammer\bin>jtagconfig --debug

1) USB-Blaster [USB-0]

172560DD EPM(3256A|7256AE) (IR=10)

Captured DR after reset = (172560DD) [32]

Captured IR after reset = (155) [10]

Captured Bypass chain = (0) [1]