Hi Lucy,
This isn't an area I have any specific expertise in, but I wonder if you could give any more detail about exactly where you get to and what happens.
Are you able to carry out any reconciliation between OpenRefine and the wikibase?
Is there any information in the OpenRefine console when you try to add items to the wikibase?
Do you have any authentication setup on your wikibase?
What does your schema look like when you try to add new items?
These are slightly scattergun questions but aimed at the places where I could see things going wrong in the attempt to create new items in a wikibase - any other detail or information you can offer may help me or others diagnose the problem.
Best wishes
Owen