1062 Duplicate entry .....for key 'PRIMARY' Problem NEED HELP

Hello, Problem arised whenever i add a product, right after i press the insert button this message pop up and i want to know how to fix it. Now it comes up everytime, when i add my product.

1062 Duplicate entry '18-2' for key 'PRIMARY'
in:
[insert into products_to_categories (products_id, categories_id) values ('18', '2')]
If you were entering information, press the BACK button in your browser and re-check the information you had entered to be sure you left no blank fields.

Thanks in advance
Kelvin

Have you found the solution to this problem ?
Because I have the same problem and I don't know how to resolve it for the moment.

Charles

I also have the same problem, does anybody know how to resolve this?

1062 Duplicate entry '0' for key 'PRIMARY'
in:
[insert into product_extra_fields (products_id, extra_field, video_title, file_1, file_2, file_3, file_4, file_1_title, file_2_title, file_3_title, file_4_title, video, height, width) values ('0', ' ', null, null, null, null, null, null, null, null, null, null, null, null)]
If you were entering information, press the BACK button in your browser and re-check the information you had entered to be sure you left no blank fields.

By the way, I have the Extra Field add-on installed and am using Zen Cart 1.3.9h.