Getting subscript out of range error - can't figure out why

That shouldn't be to hard, which columns do you want it to work on and what have you tried?

For example, I'd want to run the keywords on column A and C (but those may shift if I add more data to the spreadsheet). Additionally (and I'm not sure if this is standard behavior), but the text in red does not translate as such to the preview panel (only the text in the cell changes color). Is that standard behavior? Thanks!