H

W-HELP, Error opening <String>
SIC, HELP command. The Help file for a language does not exist.
User action : check with the programmer or system manager that all logical names have been correctly defined.

W-HELP, Language <String> is in library only mode
SIC, HELP command. The specified language is in library mode, no help is available for it.
User action : commands from this language cannot be accessed interactively, except by specifying the full language name.

W-HELP, No help for <String>
SIC, HELP command. The specified command <String> is not documented.
User action : unless you are quite sure of their behaviour (or you like risks) avoid using those undocumented commands.