You would need to add the module to all pages, currently I do not know of a way to achieve this globally without manually editing each individual page.
I have created a new page and put the shoutbox module there.. But when i navigate to that page, its asking for login credentials. After entering them it still doesn't login and show the shouts!!!
That is something you would need to ask vBulletin support for, due to critical bugs in vB 5.1.7 we are unable to support this version at this time.
vBulletin support have stated they are not interested in fixing a critical data loss bug for another 6 months (3 releases into the future), so we are unable to adequately support vB5 until vB 5.1.10 is released.