I'm trying to create this c clamp frame for a class project and I'm trying to use loft to get it from the smaller portion to the larger sketch. I keep getting this error and I'm not sure why. Any help would be appreciated. 
edit: Just attached the actual file
Can you upload your part?
review your sketches...when lofting from a square to a circle we would have to divide the circle up into 4 separate sketches, not sure that it is your problem but it is a place to start looking...
You need more guide "curves".
When your loft doesn't work, More guide curves is almost always the answer
Here is the model - You have some extra lines in your sketch - removed them and lofted without problem !
imho.. she wants to flow... (image attached)
Nice job, Paul
Adding guide curve really make it diff.
Christian,.. actually, I did Normal To at each end.... then,.. moved the control point until it solved. (as you had noted, the sketch has problems,.. so the control/direction is misaligned.. I did not change the sketch (contour)... just moving the control point helps it solve.)
Oh... maybe the rendering of your image fools my eyes. I thought there are guide curves and YES, applying Normal constrains also working nice too - but it's not very nice until it'd rendered
I'll raise you a Spider skin texture from Modo:
Or some gravity defying liquid drops
This is very cool stuff, Kevin
.. and, she has been quenched!
Here is the model - You have some extra lines in your sketch - removed them and lofted without problem !