Thanks for the replay i discover that this happens on servers that have mod_security installed and set on, there is a work around on the net when this happens adding an htaccess file with
#Desactivando mod_security.SecFilterEngine Off
But that did not work for me, the problem was the server when it had the iso-8859-1 it displays the link (searching keyword Ñame):
Now in UTF-8 the link of the search for Ñame displays
Now if you can see the difrence how it looks Search_pro=%D1ame with Search_pro=Ñame
With the iso-8859-1 i was getting on the server an error page (HTTP 406 Error: An appropriate representation of the requested resource… )
So what i did was change everything to UTF-8, opened up phpmyadmin clicked on operation changed the collition of the database and then of every table and cell, this works so so cause now when its utf it doesnt distinguish spanish or latin characters that are capitalized or not Ñ or ñ wich doesnt happen with the normal english characters K=k but with special characters they seem to be diferent Ñ!=ñ, i checked the database to see what codes are placed for special characters so in it ñ=Ã± and Ñ=Ã‘ so for now i added a msg on the search if your search didnt work test capitalizing first character or bla bla bla, guess its more a mysql and the server settings but on others server the iso-8859-1 works just fine with no problem.
Sorry my poor english