AS Roj mentioned, the install disk have an 68040.library placed in the libs drawer. If you copy all the libs needed for the Blizzard 1260 (if you have enough free space on the disk) then this problem should disappear.
I dont know if it's enough just to erase the file, as I haven't tried it; I just load the Workbench disk, and then load HDToolBox from the Install disk.