EDIT: Oh, I see you're using an older version for 1.4.2. I'm not sure how to solve that then. The mods might just be incompatible using those versions.
That's why I asked, because it seemed wierd to me that the mod set I've been using the last couple of months worked fine (little to no crashes) when I used them via installing the mods directly (via jar and mods folder) and worked fine when I used them with Magic Launcher, but using them with Multi MC would make the whole thing throw up the minute I included Twilight Forest.
I was kind of hoping that you or anyone else here might have come across the same problem with the past version while using MultiMC , and would have any insight on what's happening with my crash reports up there.
Fingers crossed, hoping not to run into the same issues when I update to the later versions soon.