there’s a problem with sweep2 on mac right now and this appears as if it could be another example of it (but i only quickly glanced at the file)… marlin has said he found the issue and it will be fixed in the next release… so, maybe wait til it comes out then retry.
http://discourse.mcneel.com/t/sweep2-error/7798
[edit] hmm. maybe not… i still haven’t fully looked at the file but maybe this is something different… i’m not quite sure the input geometry is fully aligned properly though… but one of these guys with windows should be able to find the difference if it’s the same/similar error happening as the one in that link above.