Rows 19 and 20 were discovered by another website that were found to have errors. I myself ran into problems on row 29 and altered the row, and it's worked fine for me ever since (I'm about 22" from top to bottom down the middle now into my shawl).
I made a Microsoft Word document with the corrected pattern at
if you would like to view it. For my own reminder, I put all of the rows where you have to cast on at the end in red, bold, and underlined print, because I kept forgetting to do these.