Suggestion on determining the device directory...
If the Microchip MPLAB IDE is installed, this registry entry will contain a string value indicating the location:
HKEY_LOCAL_MACHINE\SOFTWARE\Microchip\MPLAB IDE\DeviceDBDir
If the DeviceDBDir entry is blank, you might inform the user that the Microchip MPLab IDE must be installed prior to using WxPic.
If it is non-blank, you could attempt to use the entry as the device directory.