In order for a user to copy a question from one question pool to another, they must refresh the question pool listing page to view the available pools. I have been able to replicate this in our local prd/stage environment and Generic Sakai 2.6.x-qa (rev. 76098).
Steps for replication:
1) Add a question to a question pool
a) I tested with T/F and multiple choice
2) After creating the question, click on copy
3) You will notice that the question pool list is blank.
4) Refresh the tool
5) Go back into the question pool and copy the previously created question again
6) The list of question pools is now visible.
You can also watch a screencast here (showing the bug in our local instance) http://screencast.com/t/YTY0MzkwY