Hi and thank you... i've done ! ... here the steps
step 1: enable production mode in Global Configuration options
returned error: Could not save data. Error: %s
... don't mind.
step 2: enable Joomla Articles Integration on SPPB settings
Step 3: create webpage (article) Test_1 (containing Articles Add-on)
Step 4: create category Lamps
Step 5: create 6 articles... Articolo 1, Articolo 2, Articolo 3 ecc
Step 6: assigned to those articles Category Lamps
Step 7: assigned one image each article on Images and Links tab on editor
(step 5, 6 and 7 at the same time)
Step 8: check the webpage and... error still again
Step 9: assign 300x300 px size to Thumbnail on Blog options
Step 10:check the webpage and... error still again
Try yourself !!!