I am working with MS Excel files in my web application built in Azure environment. I never run into following error when I am trying to access the excel file on my developme
That means the DAC is not installed (Data access component).
http://www.microsoft.com/downloads/en/details.aspx?familyid=7554f536-8c28-4598-9b72-ef94e038c891&displaylang=en
Don't know about Windows Azure however.