Help with a IIe and Disk-2

[delafo@oxy.edu (John de La Fontaine)]

Help! I am having an aggravating problem trying to use Disk #2
on a IIe (enhanced).
Appleworks and Publish It encounter a read error when trying to
access Disk 2.   I have ascertained that the disks involved are NOT
write-protected. Disk 1 will read these disks just fine. 
I put on another disk drive to see if the drive was the problem and
had the same error.  I installed another Interface card and still have
the same error. I even made another copy of Appleworks to make sure that 
it wasn't corrupt.
Until this error creaped in, the machine was functioning just fine with
2 drives -- drive 2 being for data. 
Is there anything anyone can suggest? I'm baffled in trying to find the cause
of this error.