It is a rather common problem with OS4 classic. I had the same trouble that made me lose many hours wondering why. I suppose you did half of what the OS4 manual suggests. Now, boot with the OS4 floppy and have your cd-rom attached on the primary port as slave. Let it work for you and as soon as you reach the Installation procedure at the very moment it asks you to install disk and refresh its RDB JUST DON'T DO IT. Use MEDIA TOOLBOX in order to set up the new partition and add FFS (Add filesystem) from OS4 cdrom. Don't forget to include the option regarding Long Filenames. Also don't forget to change the DOS 03 digits to 07. Confirm every change/option by always pressing ENTER. Continue the installation, finish it, switch off for 20 secs and off you go (hopefully). For the first time you will boot it would be a good idea to have only OS4 partition as bootable, so disable the other other, in order to see if you have set everything right and that the system reacts well. The Amiga, most of the times is a really temperamental and picky system.
