"invoice already been paid "paypal documentation

Hi,

As per hikashop paypal documentation:
"It is possible for Paypal to report an order as already being paid if they have received an identical invoice number in the past. That can happen when for example you were already using another e-commerce solution before switching to HikaShop with your PayPal account.
There are a couple ways to resolve this issue:"

my questions:
1-Should I change both side in my Paypal Account and the HikaShop side?

2-Please see attachement and tell me is this where I should run a query on my cpanel- php myadm- SQL tab?

how? copy and paste ALTER TABLE jos_hikashop_order auto_increment = 100000? I am not good in database can you tell me how to do it? Thank you so much.