I can't actually tell you what is wrong with your
Submission without looking at it. However it should be noted that split CDs are formatted differently to regular CDs (one artist).
here are some examples of the correct layout on the submissions guide.
http://www.spirit-of-rock.com/wiki/index.php?title=Submission%27s_Index#SPLIT-CD_TRACKLISTS
I remember having fun once, it was terrible...