Hello.
Please follow these steps:
1. Navigate to Admin > System > Setting > System.
2. Ensure your Debug level is set to 1.
3. Confirm that the Cache is enabled and using the FILE driver.
4. Set SEO URLs to OFF.
5. Go to Admin > System > Cache and clear all caches except for images.
6. Create a new product with the following settings:
the status On
assigned to the Default store;
the Date Available is in the past (if there's a time mismatch between your server, your database server and PC)
quantity 1
7. If the problem persists, check the AbanteCart Error log