Actually, I checked via your portfolio. I just went to the log and it looks like the link didn't work, so you probably used your Item ID as an Entry ID.

The difference is, Entry IDs are for sub-units such as the individual chapters in Book items. You've posted static items, so you want to use Item IDs.

Note that you don't actually have to post these assignments, except for the contest round assignments on Saturdays (if you want to compete in the contest). If you are a free member, you will run out of items long before the end of the month, so you might want to save your available items for the contest rounds.

...
Regards,
Eric Fretheim
Assistant Prep Leader, 2015 October NaNoWriMo Prep Challenge

"It is perfectly okay to write garbage-- as long as you edit brilliantly." ~C.J. Cherryh

“No, writing 50,000 words in a month is normal. You are not crazy. This is not insane.” ~Teri Brown