In this case the relevant DLL file vcXextse.dll(Virtual CD v8 and newer) respectively vcXextse64.dll (Virtual CD v9 and newer) is either not registered or no longer registered.

Solution:

Click on Start -> Run, then type

• regsvr32 "[Path to]\vcXextse.dll" (32-Bit and 64-Bit Windows, Virtual CD v8 and newer), i.e. "C:\Program Files\Virtual CD v10\System\vc10extse.dll" 
• regsvr32 "[Path to]\vcXextse64.dll" (64-Bit Windows, Virtual CD v9 and newer), i.e. "C:\Program Files\Virtual CD v10\System\vc10extse64.dll"

HINTS:

• Please replace the X in VCxEXTSE.DLL and in Virtual CD vX with the corresponding version number of your Virtual CD version.
• In Windows 64-Bit a COM Server(vc10fwd.exe) routes the commands from 64-Bit to 32-Bit.
  For example check in Taskmanager if the process vc10fwd.exe is started while you open context menu of a virtual CD drive.
• The Virtual CD Explorer Integration does not work with FCD-Images created with Virtual CD 1 to 3.