cleartool protect -chmod 770 <vob-tag-name> ERROR

Question

This command does not work:

cleartool protect -chmod 770 <vob-tag-name>

i get the following error:

cleartool> protect -chmod 770 vob-tag-name

cleartool: Error: Unable to access "vob-tag-name": ClearCase object not found.

The VOB tag is valid and points to the correct VOB location.

What am I doing wrong?

HELP!

Thank you!