A1200 Yellow Screen

[da9000]

Your problem could be related to the Max Transfer Size variable used by the file system:

http://www.unitechelectronics.com/ideproblems.htm

and a visual tutorial:

http://www.newtek.com/support/tech/faqs/amiga/vt/tutorials/index.html

You can also find tons of references to this by using the crappy search function on these forums.

Good luck!