E0009585 error after upgrading to vCenter 6

hi,

we're running backup exec 2010 r3 and recently had vCenter running 5.5.

However I recently upgraded vCenter to 6.0 and now every job which backs up a vmdk file fails with the error:

E0009585

V-79-57344-38277 - Unable to open a disk of the virtual machine.

VixDiskLib_Open() reported the error: One or more required subsystems failed to initialize

I've had a look at various KB articles and other support threads but nothing in there has worked for me.

Does anyone have any idea how to resolve this?

Thanks