This script works fine for me. You need to install entware for it to work. If you have entware installed, just type opkg install dropbox-upolader, after that navigate to the entware/bin/ directory, and run the script from there (./dropbox_uploader). You get step by step instructions then, just follow them. After initial setup, the script has to be run as a cron job, otherwise it stops after you close your Telnet / SSH Client.
I have found that the script works better than the AiCloud dropbox support, it uploads faster, and there is no 2 Gb limit (i have dropbox pro, but i could not upload any files larger than 2 GB with AiCloud).
Are you familiar with SSH/Telnet configuration of your router? If you need more detailed instructions, just ask.