I've found that if uninstall the the desktop app and reinstall I can sync with my reader once. After that it hangs or is taking so long to do anything that may as well be hung.
I've installed the update listed above, I'm running XP SP3.
What seems to be the killer is that it has to download the books I've bought every time it runs. I can understand once, but every time? I've bought 3 books and with each on the time to download gets long. 3 is not so bad but what happens when I get to 13 or 33? I'll tell you what happens. I'll not get past 3 books. I'm not buying anymore until this get ironed out.
What really worries me is that the Firmware updates are supposed to get to my ereader via this software.