If you receive the following non-delivery report (NDR) when sending internet mail with outlook9x,
it is because Outlook9x can't write to the %SystemRoot%\System32 folder:
No transport provider was available for delivery to this recipient. The service is installed but doesn't show up in Tools/Check for new mail on...
Outlook9x must write a MSINxxxx.RHC file, the first time it sends internet mail, where xxxx is a different number for each user.
The default permission on the %SystemRoot%\System32 folder is Everyone Read (RX). You must set it to Everyone Add & Read (RWX),
Replace permissions on Subdirectories and Replace permissions on existing files.