Silly question, are you certain you are using the vWii d2x v10 installer files? There are ones for Wii and vWii. The vWii version is not supposed to download anything from NUS but extracts what it needs from the console...unless of course it is not getting what it needs I guess. You can try putting the IOS wads for the vWii on the root of the SD card and running the installer again.
Yes I am using the d2x cIOS Installer Mod v2.2 with d2x-v10-beta52-vWii.zip or d2x-v10-beta53-alt-vWii.zip and both fail
From:
d2x cIOS Installer Mod v2.2 (this version patch on the fly original IOSes dumping them directly from your vWii); download and extract folder \d2x-cios-installer mod v2.2 in SD :\ apps <-- (needed to install cIOS)
d2x cIOS; download and extract folder \d2x-v10-betaXX-alt-vWii INSIDE \d2x-cios-installer mod v2.2 folder; choose version d2x-v10-beta52-vWii or d2x-v10-beta53-alt-vWii according to this pros/cons official chart: