This is probably not a DP problem, these are IO errors that, in the case of a tape drive, would indicate some kind of hardware problem. The 'Details Unknown' part of the error usually indicate a driver problem of some kind
If possible, try doing a reboot of your VTL device, this has at least an even chance of fixing the problem
You don't say what the OS-type is on the media agent, but if it is UNIX-based, you can load a scratch media into a drive, and see if you can 'tar' to it. It is not possible to do thsi with a Windows-based media agent