Your previous question has been solved. OK?
If you have new question, then you should create a new Forum discussion. You should not continue adding comments to the previous discussion. The title and contents should be in sync, as you know.
Please create new one.
Also, please share your test case code as well. Pasting log is important but not enough to find out why you are told (Root cause: java.lang.NullPointerException: Cannot invoke method getAt() on null object)
Please have a look at the guideline [TIP] My test is BROKEN! NOTHING WORKS! PLEASE HELP ME!
Which version of Katalon Studio do you use? the latest 5.10.1? If not, is it possible to upgrate it? because I suppose the 5.10.1 would give you more informative error message.