What are cltLMS1.dat and cltLMS2.dat

I have Dell studio 15 notebook running Win 7 Pro SP1 32-bit, with NIS 2011. When I did manual full scan, it started fine, ran for a while, and quit suddenly way before the progress bar reached 100%. There was no dialog pop-up confirming its completion. Suspecting something bad, like a rootkit malware, I downloaded several tools (Norton, MalwareBytes, Sophos Anti-Rootkit). Sophos flagged these "unknown hidden files" in a Norton subfolder:

 

C:\ProgramData\Norton\00000082\00000109\000003c6\cltLMS1.dat

C:\ProgramData\Norton\00000082\00000109\000003c6\cltLMS2.dat

C:\ProgramData\Norton\00000082\00000114\000004e7\cltLMS1.dat

C:\ProgramData\Norton\00000082\00000114\000004e7\cltLMS2.dat

 

I tried deleting them, but they reapeared after rebooting. I googled these filenames; ThreatExpert website stated they were indicative of either the Virus.VirTool.Win32.MS04 [Ikarus] or the Trojan.Graybird (also has other names). But other websites were inconclusive. Are these valid program files (& Sophos raised a false-positive)? If not, what will remove these? I tried many other anti-malware tools but they did not detect a problem, even in Windows "safe mode". NIS 2011 manual full scan ran fine in "safe mode" with no report of malware.