False reports of trojans

gday again people, i have been having issues with a few nodes that keep reporting some files as being malware/trojans.
All it says is.
Determination:Bad
Malware Group:W32.Trojan.Gen
Global Popularity:14
Console Popularity:1
Determined:Feb 3 2015, 3:55
Filename:PDFVIEWER[1].EXE
MD5:680BFAFC0B1019296B6915A149AAD64D
Pathname:%cache%
File Size:245.6 KB
Product:WMI SNMP Provider
Version:5.1.2600.5512 (xpsp.080413-2108)
 
Can i ask where %cache% is as a relative file path?
I also had one user have a file called SEX[1].exe but he denies all accountability and doesnt know what it is.