Sorry, but I need to see the html code aroudn where the links should be showing up but aren't.
But really, we can't help with your custom style - only the designer can. We can help with your default style. So, you should see if you still have the problem using the default style:
Create a new style with no parent:
- Styles & Templates > Style Manager > Add New Style
- Parent Style: No Parent Style
- Title: Default vBulletin
- Allow User Selection: Yes
- Save
Then browse the site using that totally default vbulletin style - do you still have the same problem?