Is this really a Trojan?

I have just completed a scan with Malwarebytes and it is telling me I have a Trojan.Agent. I am assuming it is a Trojan virus but it hasn't been picked up by NIS 2010 and it doesn't look like one!  The file is:

 

C:\Program Files\Norton Internet Security\Engine\17.5.0.127\msl.dll

 

Why would this program be picking this up if it doesn't need removing?