数检报告疑问(CHECK)

-----------------------------
| vertical load information |
-----------------------------
Floor No. 1 Nload = 753
Floor No. 2 Nload = 753
Floor No. 3 Nload = 753
Floor No. 4 Nload = 753
Floor No. 5 Nload = 886
ERROR 1011 : X4 < X3 or X3+X4 > Lb, No = 46 Lb = 4.30
ERROR 1011 : X4 < X3 or X3+X4 > Lb, No = 52 Lb = 4.50
Floor No. 6 Nload = 630
Floor No. 7 Nload = 630
Floor No. 8 Nload = 630
Floor No. 9 Nload = 630
Floor No. 10 Nload = 630
Floor No. 11 Nload = 630
Floor No. 12 Nload = 630
Floor No. 13 Nload = 630

竖向导荷出现的问题,麻烦给解释一下出错原因