< > Previous product and Next product;; problems

Hi,
I have re-ordered all of the products of one category, but but within the website the <> buttons either don't display or where they display one press jumps many places,, ie the first product J0001 does not display the >... if the second product is opened "J0002", it displays both < & >... When > is pressed it jumps to J0014 even though the order is linear; J0001, J0002, J0003 etc; within the product category in hikershop...
Does anyone have any ideas on how to fix this..
Cheers,

Hi,

I think it's because the product is in many categories, so the request select the first category of the product and display next and previous button with the products in this category.
Try to change the order of the categories in your product edition page.