Hi Tami,
As Kirk suggested, it is mandatory that you add in the SQL security the domain user ID for the users you want to grant access to GP data.. Once the Domain User ID has been added to SQL security, you have to give them access to the individual GP company databases and the DYNAMICS DB eventually. Microsoft has built-in some useful default SQL security roles for reporting purposes, in order to grant access to users for the Excel & SSRS reports that come out-of-the-box with GP. You can use the same groups to assign to your users, so you don't have to struggle with individual table or view security.
Those default roles are all starting with rpt_xxxx in SQL.
Here is an excellent blog post from Mariano Gomez about the SQL report security with a link to the list of roles from Microsoft : dynamicsgpblogster.blogspot.ca/.../microsoft-sql-server-security-roles-and.html