You mention the Zuka theme. Sorry but the Zuka theme hasn't been updated for TikiWiki 2 and so won't work without problems. But then I see you're using the Eatlon theme so I guess the Zuka theme isn't involved after all.
About the breadcrumbs, what is displaying at Zukakakina.com is the site title ("Zukakakina.com") and subtitle ("Themes, etc. for TikiWiki CMS/Groupware"). These are displayed with this custom code, entered in the Custom Site Header textarea:<div id="sitetitle"><a href="index.php" title="
<div id="sitesubtitle">Themes, etc. for TikiWiki CMS/Groupware</div>
The Eatlon theme has CSS style information in its stylesheet to render the sitetitle and sitesubtitle divs in the font sizes, etc., that you see there. Using this custom code along with a site logo could cause problems unless adjustments are made in the theme's stylesheet. But you could try entering just the sitesubtitle information in the custom site header textarea, and see if it displays well.
The breadcrumbs feature of TikiWiki doesn't have any particular text styling as far as I know, so that's why it displays as it does at your site. Personally, I think a two-link breadcrumb trail is fairly useless, so I don't ever use it.
Also, at Zukakakina.com, there is a menu specified on the Look & Feel page. "Top Bar," "Site menu bar" are turned on and the menu id (of a custom menu that has fewer items than the default menu and therefore fits better) is specified.