The lockername is cmps012a, the assignment is hw3, or hw followed by whatever the current number of assignment is.
There have been some problems with submit. If it is not working, Log onto one of the main cats machines: si, am, or ese, and try submitting from there.
The -lm is needed when you include math.h. It is last because it is done at the linking stage, and is predicated on the object files.