Hi Davide I did the procedure to insert the AEN code and load the products in complete tranquility ... But unfortunately I was not able. How can I do?
Did you mean EAN (European Article Number)?
I assume you have been following the Automatic Product Mapping by Unique ID process by adding a custom field e.g. "ean" to your database and using the script to apply the mapping after cron.
Where in the process have you managed to get to so far? If you have added the custom field, make sure that you have re-registered each of your feeds that have an EAN field and mapped the field just like the standard fields, and then re-import.
Then, to double check that they have imported correctly go to Tools > Feed Utilities and click Imported Analysis next to the feed that you have just re-registered and re-imported. Click on a couple of products and check that the EAN value is showing in the product records displayed.
If that's all good then it should just be case of setting up uidmap.php to run as part of your cronjob after cron.php as described in the above thread. If still not working as expected let me know where you have got to in the process and I'll check it out further with you...
I respected the whole process but I have an error: as soon as I load everything, the feed is cleared. How is it possible?
That sounds like a database error is occurring at import time - please could try to import a feed with database debug mode level 2 by changing line 6 of config.advanced.php as follows;
$config_databaseDebugMode = 2;
Then import a feed and the database error should be displayed. Let me know what is displayed (or if there is no difference of course) and I'll check it out further with you...