When I'm stopping snapshot (on iSCSI-R3 Enterprise 2.30 build 2820) software MSiSCSI 2.05 (on W2K3srv, WXP) generate error:

iScsiPrt event ID: 20
Connection to the target was lost. The initiator will attempt to retry the connection.

Volume as target only connected to iSCSI-R3, snatpshot not connected.
How can I eliminate this problem?