I think I just ran across a very similar problem (brand new install of ROS Fuerte on a clean install of Lubuntu 12.04, then installed ST)
I had a test script that worked fine from the command line (python xyz.py), but was erroring out when I tried to run it from inside ST with this error:
ImportError: No module named cv2
I found a similar issue here:
End result, the PYTHONPATH for ROS was different.
So my customized python build script looks like this now (called rospython.sublime-build)
"cmd": "python", "$file"],
"file_regex": "^ ]*File \"(...*?)\", line ([0-9]*)",
Hope that helps or is a starting point for someone else with the same problem.
(note: I haven't tried rosmake from within ST, so this might be a different issue, but it sounds similar.)