Are you also experiencing the following Outlook 2010 warning during startup ?
Either there is no default mail client or the current mail client cannot fulfil the messaging request. Please run Microsoft Office Outlook and set it as the default mail client.
In that case you need to do the following:
* Delete the registry key:
32bit: HKEY_LOCAL_MACHINESOFTWAREClientsMailMicrosoft Outlook
64bit: HKEY_LOCAL_MACHINESOFTWAREWow6432NodeClientsMailMicrosoft Outlook
* Start > Control Panel > Programs > Programs and Features, select Microsoft Office 2010 and click the Change then do a repair