From the IBM website:
DAMO: Send To > Mail Recipient from Windows Explorer does not send mail
Technote (FAQ)
Problem
On Microsoft Windows XP, you have the ability to right-click a file in Windows Explorer and select Send To > Mail Recipient. Explorer then loads the default mail application such as Microsoft Outlook, creates a new mail message, and attaches the file to it. You can then add your recipient name(s) and select Send. The message should send and the application should shut down.
On Windows XP with Service Pack 2 (SP2) installed, this functionality works up to a point. The mail message is loaded in Outlook but when you select the Send button in Outlook, nothing happens. The message does not get sent, and Outlook remains open with the message in your Inbox. You then have to reopen the message and select Send again for it to go. This affects Lotus Domino Access for Microsoft Outlook (DAMO) since DAMO runs on top of Outlook.
Solution
The Windows XP SP2 Firewall is known to cause this issue. Either the firewall must be disabled or Outlook must be added to the firewall settings as an exception.
To access the Windows Firewall settings (to either disable it or add Outlook as an exception) select Start > Control Panel and double-click the Windows Firewall icon.
This issue is not specific to DAMO.
Regards
Mark