First check that you have closed floor panels, formed by beams on all sides, within the X,Y,Z range that you have specified in your oneway load command. It may be better to use two different values when defining the range. For example instead of using YRANGE 231.97 231.97 , it is better to use YRANGE 231 232. Also you should have the direction specified at the end of the command line for example the GY command at the end as shown next.
So
ONEWAY LOAD
YRANGE 231.917 231.917 ONE -0.01 XRANGE 63 90.5 ZRANGE 55.5 58.5
should be specified as something like
ONEWAY LOAD
YRANGE 231 232 ONE -0.01 XRANGE 63 90.5 ZRANGE 55.5 58.5 GY
An example showing a one way load applied using reference load is also attached for your reference.
(Please visit the site to view this file)