Q: The alert "Operation can't be completed." keeps popping up on entering Time Machine

When I was copying a big folder to a HDD that I use as the Time Machine storage, Finder crashed halfway. After that, I opened Finder and entered Time Machine, and an alert that says "Operation can't be completed." popped up with no error code on it. Even if I hit the OK button, it keeps popping up and I can't have my mouse focus on the Finder window because there's always that alert over it. Once I get out of Time Machine and force quit Finder via Activity Monitor.app, it goes away, but it just reappear once I get back into Time Machine. I rebooted, deleted ~/Library/Preferences/com.apple.finder.plist, repaired the HDD in Disk Utility.app (there was no problem), and deleted inProgress package in my backup folder but it just doesn't go away! How can I kill all the alerts? Help!

OS 10.8.3