I've never had many problems with disk2fdi. Is the disk a standard Amiga-formatted disk? And are you sure it's 100% OK (works absolutely fine on a normal Amiga). The only switch you need to use is /s (I think).
Also, how are you running it? Aparently you can run it from win9x OK, but if you use 2000/NT/XP you need to boot to a DOS prompt (ie use a startup disk).
