Virtual Box 64 bit Error

[Lakes]

VB Version 4.3.26 r98988
Trying to install Debian on a Windows 7 64 bit machine.
Virtualization turned on in Bios.
Hardware Virtualization turned on in Virtual Box.
CPU Quad core Q6600 supports Virtualization.
Tried disabling Avast anti virus and Comodo firewall with same result.

Unable to load R3 module C:\Program Files\Oracle\VirtualBox/VBoxDD.DLL (VBoxDD): GetLastError=1790 (VERR_UNRESOLVED_ERROR).
Result Code: E_FAIL (0x80004005)
Component: Console
Interface: IConsole {8ab7c520-2442-4b66-8d74-4ff1e195d2b6}

I have screenshot photobucket links which I can post here whwn I have permisson.

Thanks.

EDIT: have downgraded to Ver. 4.3.12 which works fine.