Having multiple issues with Outlook 2007

[Foster]

Starting Outlook 2007 get dialog box saying
"Either there is no default mail client or the current mail client cannot
fullfil the messaging request. Please run Microsoft Office Outlook and set
it as the default mail client."

then if I open an e-mail I get another error and Outlook 2007 stops working.
"The file ExSec32.dll is incompatible with Microsoft Office Outlook. Install
Outlook again."

This has happened before and I was able to fix it somehow

Beta 2 Technical Refresh