Resolving error 0x800f081f (DISM .NET3.5)
I found that installing .NET 3.5 via DISM /enable-feature option after installing language packs will produce the error 0x800f081f.
So, just uninstall the language packs and it MIGHT work smoothly.
This is tested on Windows 8.1 Pro VL with Update 3 x86.
Note that this is only one of the possible reasons of 0x800f081f error. Inserting wrong DVD/mounting wrong ISO might be the reason too.