It might be worth installing the smp kernel on your dual core processor machine. I would also suggest that you setup your core as a Hybrid Core so that you have the option to use it as an MD... even if that is only in emergency situations.
My core is single core. I just re-installed it as Hybrid.
My dual core MD does not boot probably due to what you are saying. It does not load the smp kernel.....
Is there a smp kernel to boot from on my single-core installed hybrid?
Do you know how to force the MD to use the smp kernel?
Hmmm... well that is a subtlety to your setup I had missed. You have a single Core processor in your Core/Hybrid but a dual-core in your MD. At present whatever kernel you choose in the initial Debain part of the installer is the kernel that will be used for all PLuto MD's too. It might be possible to update the kernel post install of the MD... but I have not tried that and i would not recommend it to you.
So you could try this... re-install again and this time select the smp kernel on your single core machine... this should work in my experience. Then when you add your dual core MD it will get the smp kernel and then hopefully it will boot ok.
If this does not work then I would get in touch with Pluto support directly and ask one of guys (probably radu.c to look into this for you).
Best of luck