Have you even come across the error above?
Below is a CADclip on a tip when applying a solid sweep where a straight segment in the sweep path transitions to a non tangent arc. The underlying tip is, if you keep running into the "can't create sweep" where you have a "path" and "profile" that do abide by all the rules, use "sketch path" instead of "pick path" and you find the sweep works ok. I suppose if you ever get the error anytime using solod sweep swith from 'pick' path to 'sketch' path anyway and see if it solves the problem. Always remember to check your work plane as well.