When sending an email you get the message:

Could not load file or assembly 
'Microsoft.Office.Interop.Outlook Version=12.0.0.0 Culture=neutral...'
The system cannot find the file specified.

Your PC is lacking some Microsoft components for Office 2007 called the 'Primary Interop Assemblies' (PIAs) that allow other programs to interact with Office programs e.g. Outlook and Word.

The full set of Office PIAs can be downloaded from here:

http://www.microsoft.com/downloads/details.aspx?familyid=59DAEBAA-BED4-4282-A28C-B864D8BFA513&displaylang=en

The relevant file for Outlook is Microsoft.Office.Interop.Outlook.dll version 12, which can be placed directly in the 'bin' folder of your PROJECT in a box installation if necessary. Download a copy 2007 here:

outlook_interop_2007.zip