Getting nothing when calling fnd_message.get()

This has nothing to do with Order Management, but I couldn't find a community area for general-purpose FND issues.  Maybe someone can find one and move this post to it.

When I issue a call to fnd_message.get in a package, its returns a NULL.  Here is an example of a stored procedure in which fnd_message.get returns nothing:

PROCEDURE generate_email_body_hasp_new (
                   p_passcode            IN  VARCHAR2,
                   x_email_body          OUT VARCHAR2,
                   x_status              OUT VARCHAR2,
                   x_status_msg          OUT VARCHAR2)  IS

  l_email_body                    VARCHAR2(2000);
   l_temp_email_body               VARCHAR2(2000);

BEGIN

   fnd_global.apps_initialize (1855, 51952, 20003);