How can I fix Splines not setting?

Hello, forgive me if I sound a bit odd in this question. Can any one please tell me why I am unable to place a single Spline on my landscape so I can use it for a path or road? Rarely I can get one to sit down and then a second then no more? Most of the time, I get none at all. Also, I have been noticing that when I place a spline down and use the deform landscape to spline button, it will not even work. Do I need to use the Ramp option in the Sculpt section to make a road or path instead? My landscape is placed by tiles in the levels tab not imported as a single map. Any one able to shine a light on it? Thanks in advance.

Been a while since I posted this message asking for help. Does any one have any idea how to solve this issue?