When you want to label your tapes, you faced with the following error:

Reference: http://seer.entsupport.symantec.com/docs/265914.htm

16.11.2009 17:13:47 – expected media FSD300; found media D300L4
16.11.2009 17:13:47 – end Label; elapsed time: 00:03:43
media manager found wrong tape in drive(93)

From GUI, after clicking right-clicking on your tape, ensure that “Verify media label before performing operation” checkbox is cleared.

Then retry your labeling operaiton.