Xmarks login isn't working and corruption on pc

When I log onto my XP, Xmarks comes up asking for my username and password. It just started doing this recently, and every time I tell it to remember my password, but it always asks me when I log on. When I open Control Panel>User Accounts>[myaccount]>Manage my network passwords, it says I don't have any network passwords, even after I log in to Xmarks.
The other problem is that when I open IE, Xmarks says that data on my computer is corrupt and asks me to either overwrite server or computer data. Xmarks for FF works fine, and so does my.xmarks.com

Are these related? How do I fix them? The first problem isn't too bad, but the second worries me.