@j.vonstetten 

Do you have a cost for those items that are showing an asset value of $0.00?  Post a screenshot of the product setup screen for one of those items.  Also, you can double-click on the $0.00 asset value on the report and QBO will show you the details of how it's calculating $0.00.  If you set up items at $0.00 cost and then manually add them to inventory, that is what the report will look like.  The report probably isn't messed up, it's more likely how you're entering your inventory.  Are you using bills or expenses when you purchase inventory?  If not, how are you adding quantities to your inventory items?

The Inventory Valuation Detail report requires that you add items to inventory with a cost using a bill, expense or check.  You can add them manually using an Inventory Quantity Adjustment but you need to have a cost for the product. If you don't, the report will look as your does.