backup error in event viewer

[M3Parker]

I'm getting this error almost every night we do a backup. any idea what it is about?
-----------------------------------------------------------
Adamm Mover Error: Unload Status Failure!
Error = ERROR_NOT_READY
Drive = "DELL 1"
{0251FC8E-F2D0-4769-82C8-1684F0E93219}
Media = ""
{00000000-0000-0000-0000-000000000000}
Read Mode: SingleBlock(0), ScsiPass(0)
Write Mode: SingleBlock(1), ScsiPass(1)

 

[Smorgan11]

try changing the SCSI cable and SCSI Timeout