links in admin--> error 404

[eskaigualker]

When I log into backoffice, certain links, as the ones to edit categories are like this:

 

http://myweb.com/admin/index.php&id_category=2&updatecategory&token=846c06b28438a15fa91aaec

 

which leads to a 404 error.

 

I see first parameter is preceded by a "&" instead of "?".

 

But don't know how this is generated.

 

Thank you