EXPLANATION This message should occur only on a down-level computer. Any action to correct the problem should be performed ...

EXPLANATION    This message should occur only on a down-level computer. Any action to correct the problem should be performed on that computer.  The workstation to which you are trying to forward the  message alias has no room for new aliases.    ACTION    Ask the user on that workstation if an existing alias can be deleted so yours can be added, or forward your alias to a different workstation.