Site redirection problems

[eluser]capypara[/eluser]
Hi guys, I have problems with navigating through my site.

Assuming I have the 2 links below (they are not related to the other, just using them for examples);

Code:

<a href="/login"><img src="/images/bird.png" alt="Bird Pic"/></a>

Code:

<form method="post" action="controllername/search">

When i try to click on the first link, instead of taking me to www.host.com/application_name/index.php/controllername/login, it takes me to www.host.com/application_name/login instead. The picture of the bird doesnt get displayed as well. I have the folder in www.host.com/application_name/images

For the second link, its a search function on this page

www.host.com/application_name/index.php/controllername

and when i click the link its supposed to take me here, where the search button still exists so that users can search again.

www.host.com/application_name/index.php/controllername/search

The first time i do a search i get redirected to the link just fine, but for every other click after the first one, controllername gets added to the URL and the link becomes like this (in this example I pressed the search button 3 times)

www.host.com/application_name/index.php/controllername/controllername/controllername/search

Needless to say my functions didnt work after the first click. Can anyone point out my mistakes? Thanks for reading the post!