duplicate link words !

i have my new review bolog com
i have categories and subcategories
when i used the tag /%category%/%postname%/ in permalink structure .
my posts dont appear in subcatories, “posts appear only in main categories with 404 errors in subcat. links”

after that i used /%category%/%category%/%postname%/
yes, iam happy , my posts appears in main and subcategories
but the prolem now , in link strucure
i have duplicate link words
example:i have main cat, Internet and sub cat domains, and post Godaddy in subcat Domains
so my links appear
http://www.xxxxxxx.com/internet/domain/internet/domain/godaddy-com/

what can i do to prevent this duplicate link words
i see many blogs uses subcategories and i didnt see this duplicate link

what can i do??