Need help, 5.25 disks and IIgs

[labelas@hotmail.com (Labelas Enoreth)]

Ok, here's the problem. I can't seem to get any disk imaging programs to
work on my IIgs. DSK2FILE will write the image back to disk with no
complaints, but the resulting disk breaks into the monitor right after it
boots. Asimov reports a GS/OS error, of, I believe $4B when trying to
write an image back to disk (It doesn't even begin to read or write).
DOS33Copier either starts to boot the disk and hangs on the loading
screen, or immediately resets. And this happens with both .dsk images I've
had on my HD from various downloads in the past, and disks that I had just
imaged right before. I never had this problem on the IIe card, so I
wondered if there's something different in the IIgs setup to break this.
Does anyone have any advice? The setup is a IIgs rom01 with 1 5.25, 2 3.5,
1 Apple External HD...1.5mb of RAM...GS/OS 6.0.1...