I am trying to recreate a song using midi in my DAW (I use cubase). The song is in 12/8 time. I thought I was doing everything right except when I finished the first few bars I played back and discovered that the music was playing back really slowly. Then did I discover the little dot next to the quarter note symbol at the top of the page next to the BPM. Does this have something to do with it? Here is an image of the top of the sheet music.
It certainly might.
The tempo marking is a pretty flexible thing. In this case, it's telling you that 110 dotted quarter notes should be played per minute. Whilst tempo is often specified in terms of normal quarter notes, it doesn't have to be.
As to why it's really slow, I'll take a stab in the dark and guess that the tempo in the DAW (that is, the beats per minute) is specificed in terms of quavers? If you set quaver = 110, the music will be three times slower than you want. It could also be specified in in crotchets.
DAWs have a (somewhat) bad habit of equating 'beats per minute' with 'crotchets per minute'. This is fine in 4/4, but causes the problems you are currently seeing when you work in other time signatures.
You can convert any tempo marking to crotchets per minute by multiplying it by an appropriate fraction. That makes it sound really complicated. For example, to convert dotted crotchets per minute to crotchets per minute, we start by noticing there are 3/2 crotchets per dotted crotchet. So you multiply by 3/2. It's pretty simple.