I think the last two errors about "An error has occurred in calculating the element geometry" is basically the same thing as the previous error: "''Element X has a radius/thickness ratio..."

The 2D line idealization, whether it's a beam or pipe, usually depends on the length dimension being much more than the cross section dimensions. Along this idea, but not exactly the same, is the radius/thickness ratio should not be too small. If the bend radius is too small compared to maximum cross section dimensions, the cross sections intersect at the bend, and the formation is not physically possible if this were a solid body or a real physical model. When Gary said plug numbers into the equation earlier, he meant to compare your ratio to the ratio of a working example. Just divide the "radius of curvature" by the "Outer diameter" or in this case, the maximum cross section dimension is important when measured to the pipe idealzation line at the centroid of any cross section. So divide the diameter by 2 to use the radius. 36.3/(10.932/2) = 6.64.

But "a picture says a thousand words." To make this easy, just turn on cross section display. You can usuallty see right away if this is a problem: