Mirroring stopping with error

Mirroring is spontaneously stopping and giving the following error message:

Completion probe and lock failed.

Description
This message suggests a serious operating system problem. Device driver was
unable to lock down a data buffer during a write completion process. This
indicates that data is not being mirrored to the target.

Resolution
None available.

Data is crossing a 10Mbps connection and no other errors or Site Blocking are happening at the same time.

Thanks in advance for your help.
PSC