Well having been a part time CNC programmer for many many years and professor, I try to teach my students about the problems of trying to cut a program into pieces. The problem is 2-fold, 1) Modal switches and 2) look ahead features. The easiest solution, DON'T do it. Just re-run the program.
If you are getting errors, go back into F360, and during the post, uncheck allow helical and curve moves. G33 Error: Watch the min radius setting in the operation, as WELL as the min rad setting in the post.
If this sounds all Greek, then it's time to step up the training. Time to watch some training videos (YouTube).