Ok, I think the first clue I was able to gleem from that is this line here:
Fatal error: Call to undefined function: get_input() in /home/aaddef/public_html/install/altertable-6.1-6.2.php on line 28
This is in the ubbt.inc.php file, but I believe was something new added around that time. So, my first guess is that you might have some old files floating around there instead of the actual 6.5.5 file. Take a look at your ubbt.inc.php file at the top. In the comment/header area you should see a line that says:
# File Version 6.5.5
