I’m having the same issue.
I have tried what silverman suggested and it did not work. I have tried placing <h1> … </h1> between the div id tags and then putting the url there, and again no dice.
I think it may have something to do with the fact that the <div id=”header”> tag is enclosed by a <div id=”container”> tag. The last few lines of my header.php file:
<div id="container">
<div id="header">
<a href="http://elvesubio.org/wp-content/uploads/2010/06/logo-boulder.png"></a>
</div>
I’ve made sure the size is appropriate (700 x 160) and tried placing this in the CSS as well to no avail. I’m worried that tanzaku might be disabling header images somewhere, especially since there is all kinds of jquery fade-ins etc.
See for yourself: http://www.elvesubio.org