“Samba is complaining about a missing CP850.so file.”

CP850 is the default dos charset. The dos charset is used to convert data to the codepage used by your DOS clients. If you do not have any DOS clients, you can safely ignore this message.

CP850 should be supported by your local iconv implementation. Make sure you have all the required packages installed. If you compiled Samba from source, make sure that the configure process found iconv. This can be confirmed by checking the config.log file that is generated when configure is executed.