Outlook for Mac 2011 suddenly crashes constantly

Recently, my Outlook program has started crashing every time I try to send an email.

The error report is as follows:

Error Signature:

Exception: EXC_BAD_ACCESS

Date/Time: 2013-08-26 10:28:23 +1000

Application Name: Microsoft Outlook

Application Bundle ID: com.microsoft.Outlook

Application Signature: OPIM

Application Version: 14.0.1.101012

Crashed Module Name: CarbonCore

Crashed Module Version: 861.39

Crashed Module Offset: 0x0001fc2c

Blame Module Name: CarbonCore

Blame Module Version: 861.39

Blame Module Offset: 0x0001fc2c

Application LCID: 1033

Extra app info: Reg=en Loc=0x0409

Crashed thread: 9

Does anyone know what is causing this error?

Question about Outlook Express