Problem on external lib

[Titanus]

Hi folks. Im trying to add an external lib to the project path.

here is what i am doin.
* project menu -> project properties
* select "paths" item
* click required libraries tab
* on the popup window, click archives tab
* browser find and select the lib
* ok

after tihs, im writing the import : "import tr.gov.*" but jbuilder says "package tr.gov does not exist" . Help me. What is wrong with this. By the way, when first added, jb shows no error for the api. But when i close and reopen it, it shows a warning sign besides the jar path :

Any idea why this is happening???