Loading Delimited Text File

Hello. Im an Igor Beginner and I've made a Macro to load delimited text and tell it to graph each columns. I also make a forward and a backward button so that i can scroll through the graph. But It give me error after i went through all my columns.
So here is my question, how can i tell my macro to stop and do nothing when column have no value? Or is there a way for me to tell the macro to find how many columns i have that contains numeric values and stop counting columns when it's blank?
Thank you very much.

Here is my procedure and the text i used. test1.txt (176.17 KB) open high speed Part 3.ipf (1.88 KB)