Hi Melanie,
Theres some useful stuff here:
http://www.youtube.com/watch?v=m4EWcLRzE_c (dependencies are at about 9:40)
If you search on Completion in here: http://help.totaralms.com/index.htm you'll get some useful info.
If you can send me screenshots of your settings Ill have a look if you are still having problems.
hope this is useful,
regards,
George.