I have issued and cleared the required permissions for the construction of facilities on a friendly slab. However after setting the position, NPC's, roads (S and E for two sides as per conditions) and submitting the action the following error is brought up: "a building/road is occupying part of the area that the facility or her roads require OR part of the road is in the border region".

This is an image of the construction site clearly indicating neither other facils nor roads in place to qualify this error message. When I set the roads to be built they are on the S and E of the Highrise with the starting build location being 16,1.

That's because the East of a 5x5 built at (16,1) would be in the border region. You probably want the West. =)

N
W E
S

wait...did I only just get my directions confused? /me grumbles

/me goes to check then smacks self in forehead.

"Sorry, nevermind. Go about your business and lock this thread."

This is why I once requested the directions be put in clockwise order starting with North (NESW) instead of being paired as opposites as they are currently. But people didn't like it. =(

If things made intuitive sense in this game it just wouldn't be as fun I guess.