Risk Type was 'File' but Filename was blank

I never saw this one before. On rebooting the computer Auto-Protect ran and generated 1 hit at 8:27:14. The Risk Type was listed as File but the Filename was blank. I went to look at the Risk History and actually found 3 hits. The exported log is show below.

 

Any idea what may be going on here? I don't want to try a restore because I'm not sure what Norton may have found.

 

Trojan.Gen,Quarantined,1,??????,File,??????,XPS,XPS\,Infected,Quarantine,Clean security risk,Quarantine,Auto-Protect scan,The file was quarantined successfully.,3/11/2011 8:27:14 PM
Trojan.Gen,Quarantined,1,??????,File,??????,XPS,XPS\,Infected,Quarantine,Clean security risk,Quarantine,Auto-Protect scan,The file was quarantined successfully.,3/11/2011 8:27:07 PM
Trojan.Gen,Quarantined,1,??????,File,??????,XPS,XPS\,Infected,Quarantine,Clean security risk,Quarantine,Auto-Protect scan,The file was quarantined successfully.,3/11/2011 8:27:05 PM