You probably don't want to use the calculate event, as it is triggered only when a field value changes. You can place someting like the following in the initial page's Page Open event:
getField("SUBJECT").value = info.Subject;
For more information, see: http://livedocs.adobe.com/acrobat_sdk/9.1/Acrobat9_1_HTMLHelp/JS_API_A croJS.88.396.html
The document title and author are contained in the document object's 'info' property.
for (var i in this.info)
console.println(i + ": "+ this.info[i]);
There is also a 'metadata' property for the document object, but this is much harder to process.