Please check the user permissions. The permission to confirm picklists is set up by selecting the Create check box in View Access, Sales tab.
To set this up:
Click Options, User Access.
Select the profile that needs permissions modifying, press F5 key.
Click View Access.
On the Sales tab, press CTRL+M keys to enter modify mode.
On Deliver Notes select the Create check box. The user should now be able to confirm picklists.
If the above permissions have been granted, the status of the picklist need changing from Planning to Pending.