From Stan Sieler:

You start debug and type

=errmsg (-#36, #231)

which yields: 'External error - subsys: #231 info: #36'

Since it doesn't know about error -36, you can move on to finding out what's subsystem #231. Type

= errmsg (#32765, #231)

and you'll see 'Native mode device file' (The #32765 is the "magic").

When you encounter an error that isn't in the catalog you should

1) submit an SR, because every error the system can generate should be in the error catalog:

2) Scan through the constants in the SYMOS file, looking for a match with the following commands:

symopen symos.osb79.telesup (the 5.0 SYMOS file)

env filter 'ffffffdc' (hex for -#36)

symlist ,,c (shows only constants, not types).