VSS Error 2008R2

Hi,

I have a problem. Got a 2TB drive, with 1,1TB free space plugged to a 2008 R2 server. And since 2 months I get a ID 12289 application log error, with a description like this:

DeviceIoControl(\\?\Volume{xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} 

00000000000001D4,0x0053c008,000000000015C010,0,000000000011B5C0,4096,[0]).  hr = 0x80070079. 

Tried various registery solutions, but nothing changes. Every time I try to manually backup the server I get the same error and the service stops.

Please help.