Thanks in advance!
In your struts-config.xml, you should not have key properties (like shop.showCategories etc...), replace that with real URI path. The key properties are not going to get resolved in my opinion, even if you associate the property file in that config file.
I'm using Tiles for the layout and the properties like shop.showCategories etc. are set in the tiles-config.xml which I have associated in the struts-config.xml. I think there is no mistake becouse I could see the filled Form in the Browser and the Action for storing the edited fields will be executed. The mistake is, that all fields in the form are empty after submitting it!
Could you post the section of struts-config where you setup the DynaActionForm?
Validation rules are not set!