Avast for Mac indicates malware in virtual Windows VMs

This is related to a previous thread (“Avast for Mac detects malware in Parallels Windows environments (maybe)”) but I’m starting a new thread here since it may be a more general problem. I have a Mac OS 10.7.5 machine which also runs Windows 7 in a VMWare Fusion 4.1.3 virtual machine. The Windows 7 installation runs Microsoft Security Essentials and is supposedly clean. However, when I run Avast! Free on the Mac, I get:

	<dict>
		<key>Info</key>
		<string>Marburg/Segi</string>
		<key>Path</key>
		<string>/[path]/Virtual Machines.localized/Windows 7.vmwarevm/Windows 787cf7c29.vmem</string>
		<key>Result</key>
		<string>Infection</string>
	</dict>
	<dict>
		<key>Info</key>
		<string>Win32:FakeAlert-GY [Trj]</string>
		<key>Path</key>
		<string>/[path]/Virtual Machines.localized/Windows 7.vmwarevm/Windows 7.vmem</string>
		<key>Result</key>
		<string>Infection</string>
	</dict>

There is a second VM which is also signaled as being infected with Win32:FakeAlert-GY [Trj].

Is there any way for me to tell if this is a false positive?

Since you cant disinfect the fakealert trojan from the OS X side (Deleting it would likely delete the entire VM ) try running Avast or some other scanner of the Windows Virtual machine to see if any infection is found. It is possible it was something missed my MSE.