Thanks for reporting this problem to us. The issue of the inventory adjustment screen not showing up when you select the "Adjust Inventory" option next to certain inventory items has been verified as a bug and will be corrected with a future update of the Auctiva website.
The correction of this problem has not been planned for a specific site update yet, so I'm not sure when it will be resolved at the moment. However, you are welcome to check with our customer support team periodically and we will provide you with an update on the situation if additional information has become available.
If you have any additional questions or concerns, please feel free to contact our customer support team using the web form on the following page: http://www.auctiva.com/help/requesthelp.aspx