Thanks for your reply.
No, I didn't delete the header, and in point of fact, I just checked the custom CSS stylesheet for the blog and saw that the correct URL for the #headerimg ('http://thegolddiggers.files.wordpress.com/2007/07/super-site-logoflattened.jpg') is still there.
What's more, upon further inspection of the blog itself, I've discovered that there are numerous additional anomalies in evidence: The leading between lines is different, and many of the other features that I customized on the CSS stylesheet have suddenly been lost, with custom colors that I selected for fonts now changed, and the spacing of titles out-of-whack.
So plainly, the problem isn't limited to the header; indeed, something is very wrong with the entire layout of the blog. Whether this is a problem related to ALL users of the Contempt theme or simply unique to my blog is something that I can't say at this point.
However, I checked my Updates and verified that I have a paid subscription to Custom CSS through July, and I have not in any way altered my customized stylesheets, so they should be functional, yet they're certainly not functioning properly at this time.
If no one else reports any problems with the Contempt theme, I guess I'll have to contact Support for help with my particular situation/dilemma. Naturally, following Murphy's Law, this problem WOULD arise on a Sunday, and I imagine Support won't be available again until Monday.