Try to restart windws update services:
net stop wuauserv
regsvr32 %windir%\system32\wups2.dll
net start wuauserv
and windows.
If it won't help, stop windows update services, rename download folder
%windir%\SoftwareDistribution
to
%windir%\SoftwareDistribution.old
and run windows update services again.
It it won't help, pleae let me know.