probleme with permalink and Cat.

hi all,
this permalink code work only in the main page,

/?cat=1″>link to cat N°1
it give : http://www.mysite.com/?cat=1

but it wont in other pages or postes it become like this:
http://www.mysite.com/myPoste/?cat=1
so i have allways page note fond.

Just for information, the code work perfectly if i disable the permalink

what’s the solution.

thanks