OK with winME you will need to manually setup your accounts to be scanned by avast.
ashMaiSv.exe (is the email scanner) would not be applicable if you don't have a software firewall, I assume you have a hardware firewall? If not you are leaving yourself wide open to infection, etc. Even with a hardware firewall, some also provide outbound protection, if yours doesn't then I suggest you consider one.
Did you run the avast! Mail Protection Wizard?
The server address for both POP and SMTP should be set to 127.0.0.1
The POP server name set to: username#pop.isp.com (use the actual username and ISP info)
and... SMTP server name to: username#smtp.isp.com
You can go into the Help file within the Avast Scanner and look up Manual configuration. It will take you through it step by step. It is not hard to do.
Check the avast help file for Setting up mail Protection. Switch of your email client and run the Mail Protection Wizard - Or you can set it up manually.
C:\Program Files\Alwil Software\Avast4 - look for, ashPopWz.exe - double click this and it will run the Wizard
Or see this thread for further information and advice
User's FAQ - Mail Protection.
If this not help, you, try the help file
Manual setting of mail protection. Launch your mail program and let the program display the account settings.