Go to Administration | Setup | Company | E-mail Settings, and select all the File Formats. (Mark DOCX, HTML, PDF, and XPS.) If you select a different format, does it work?
If you switch to the canned version of the report, does it email?
Make sure the dll version of the Word Add-In is up to date for Office 2007. (Go to the AddIns folder in the Dynamics GP code folder and view Microsoft.Dynamics.GPBusinessIntelligence.TemplateProcessing.dll and Microsoft.Dynamics.GP.BusinessIntelligence.Office.dll)
Do you want to know how to send and receive electronic documents in Business Central? This module explains the setup that is required to send electronic documents, and then it demonstrates how to send and receive electronic PEPPOL documents with and without a provider.