Hi. I’m new to rhino
Trying to let a profile (line) follow a path. Using _sweep1. Always had problems on windows with that. What’s my fault??? Drawing an rectangle (can’t select all 4lines) and draw some profile shape (lines and arcs). Won’t work…
Always the problems with guideline… Idk 
please share a file and some screen shots, its hard or rather impossible to say where your issue is.
also if you draw a rectangular you have one closed curve, that should not be 4 single, if so you might have exploded it or you drew a rectangular with 4 single curves, if so simply use the command join.