Same issue here in the netherlands also on a 1520 CV developers preview. I see a lot of the same issues in april.
I have 11gb storage free, freeing the temp storage and rebooting several times and retrying the update doesn't help.
The symptom is the same as earlier reported. It downloads completely, and when its on preparing install it fails around 90% with this error.
I'm still on the black version btw, cyan doesn't come although it''s already released. It could be possible that the update that is now failing is the cyan update.
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I've now downloaded the Nokiasoftwarerecovery tool (you can find a link here on wpcentral) and installed it that way. The phone is now on cyan and downloading its settings and apps from the backup so maybe it's a solution for you too.