The DoggCatcher developer has heard of similar problems, and posted some potential resolution here:http://www.doggcatcher.com/node/843
There's also this thread on Google's bug tracker:http://code.google.com/p/android/issues/detail?id=1996
I've also heard that going to the home screen, pressing the Menu hardware key, tapping Settings, going into Applications, Manage applications, All tab, then going to Market, and hitting Clear cache helps. I don't know what attendant risks are with this.
I don't have any control over the Android Market, so I can't help beyond that.