This tip is provided by one of our Symphony developers, Qiang Xu.

Scenario
You need to write some java servlet code to integrate the Symphony API with your Java EE project. But you encounter the following problem;

Error 500--Internal Server Error
java.lang.UnsatisfiedLinkError: no jnativesoamapi_3.1.0_64 in java.library.

Getting this error on 32-bit Symphony package clearly indicates that something is wrong with the configuration of your environment.

Steps

First make sure that the shell which you used to start the weblogic server has the PATH set correctly as follows;

export PATH=$SOAM_HOME/${SOAM version}/${OS type}/lib:$PATH

If the error persists, there is another solution. Copy the java native library and the soambase library to the Weblogic bin folder. Then restart Weblogic and re-deploy your application that includes the new logic of verifying your settings as described below.
There is an online BEA article that explains the way to solve a similar problem.

Verify your Setting
To verify your setting, you can use the following code.
If successful, your Initialize API will return successfully

Code:
public class InitializeAPIServlet extends HttpServlet { 
   public void service(HttpServletRequest request,
        HttpServletResponse response)
   throws ServletException,IOException{   
   response.setContentType("text/html;"); 
   PrintWriter out = response.getWriter();
   out.println("<html>");
   out.println("Start to initialize API!");
   try {
      SoamFactory.initialize();
      out.println("API initialization was successful.");
      out.println("</html>");
   }catch(Exception e){
      out.println("API initialization failed!");
      e.printStackTrace();
      out.println("</html>");      
   }    
  }
}
References
BEA WebLogic Integration