Do you have Mac OS disks to boot from? I've only had experience with Spectre 128/GCR, and real (old) Macs, but at the smiley Mac icon the system is trying to boot the OS. Unlike the Atari ST, Mac's System ROM is just like a BIOS chip, it doesn't have the OS software embedded in it like TOS does, so you need to provide the emulator with mac disks to boot from, Either a HDD image, a Floppy Disk with Mac OS files.
If you're using floppy disks you have to keep in mind that Mac 800kb floppy disks used CLV style drives, and the ST/PC uses standard CAV style. If you have actual disks from a Mac, you'll need either some hardware so the ST can properly read the disks (Spectre GCR), or you need to convert the MAC images to the Spectre 128 "Magic" format which is a fudged format that lets the ST read the data. I think to make these disk you actually had to find one already converted or get an actual Mac, serial network it to the ST and run a disk transfer program. The Mac reads the data and the ST writes it out in Magic format.
I Google searched for ST Aladin Mac Emualtor and came back to this topic on AA. Someone about 5-6 messages down states that Aladin can't read actual MAC disks and didn't last long since the Spectre GCR was around and it uses a hardware fix to make the ST drive capable of reading Mac disks without any formatting.
TL;DR - Find a Mac OS Disk in "Spectre 128 Magic Format", or get a Spectre GCR when you're done banging your head against the wall.