If you are using Outlook 2010 and Sage, you may be experiencing problems when sending emails via Sage.
This is a known issue as currently (as at August 2010), none of Sage's current versions of Line-50 are compatible with Outlook 2010.
Sage state that:
"Microsoft Office 2010 integrates with other software in a completely different way from previous versions, therefore our current products are not supported with this version"
For more information please refer to: https://support.sage.co.uk/default.aspx?page=3135