Right! I found the solution to the problem. For those that are still struggling with this ssh to your server and edit the php.ini file;
sudo nano /opt/bitnami/php/etc/php.ini
Find the line for "; sys_temp_dir = "/tmp", it should be commented out. Remove the semi colon from the beginning of the line to uncomment AND change the path to match the path of the "upload_tmp_dir = /opt/bitnami/php/tmp" line.
upload_tmp_dir = "/opt/bitnami/php/tmp"
sys_temp_dir = "/opt/bitnami/php/tmp"
Save with ctrl-x (in Nano Text editor) and Restart Server (I had to restart the server, apache restart didn't work).
sudo /opt/bitnami/ctlscript.sh restart apache **-or-** sudo shutdown -r now