Is this literally what you have?
Code:
<a href=”http://www.xxxxxxxx.com/cpanelbanner.html" target=”_blank”><img src=http://www.xxxxxxx.com/images/cpanelbanner.gif /></a>
The reason that I ask is that I did not notice it myself until I tried your code on a test server, but you have a different double-quote character after your href= tag than at the end of the link. Look very carefully:
The two characters are not the same. It needs to be the " (shift + apostrophe-key on a US keyboard).
If I surround the link with " characters, not the ” you have at the beginning, the link works as intended.