Is the window opening and you are seeing this in the new window?
What I see is part of the code for the new version of function print_textarea_row(). You need to re-do the paste-in of the new function into includes/adminfunctions.php. It looks like you copied up a little too much and got
"*/?>"
at the end. The function should end with the closing curlie bracket "}" and not have anything after that.
I no longer use this product as I have a much improved version but it's incorporated into a larger product I haven't released yet.