An ODBC connection is usually not an Oracle Database connection (you have dedicated connection types for that), therefore the tnsnames.ora isn't involved.

What are you trying to connect to?

@Tony_OAS_Apex_User ,

In Oracle BI Publisher, access to:

• Data Models
• Data Sets
• Reports
• Folders

is controlled by catalog permissions, if regular user cannot see columns, they likely don’t have required permissions.

We give catalog item access permissions to application roles.

The permissions that we can assign to others vary depending on the type of content. To change permissions, the application role that we are assigned to must have the Change Permission privilege.

1. On your home page, click Navigator , and then click Catalog.
2. In the Catalog page, search for the content to which you want to assign permissions.
3. 
   
4. In the Permissions dialog, click Add users/roles to access the Add Application Roles and Users dialog to add any required accounts. The roles and users inherit permissions from the roles of which they are members. For example, you can grant Full Control permission to the BIServiceAdministrator application role on the Sales Revenue analysis. This enables any user or application role with that role to have Full Control on the item. You can see the permissions that users and roles have on items (either granted directly or inherited). Click the Click to see effective permissions button in the Add Application Roles and Users dialog to display or hide a Permissions column to see the effective permissions for each row in the Selected Members table.
5. In the Permissions dialog, click the Permissions list. Most of the items in the list are parent permissions and contain several child permissions.
6. Optional: To build a specific list of permissions, click Custom. This option gives the user authority to bypass any permissions set on the folder that prevent the user from accessing the item from the Catalog or a dashboard. This option doesn’t change the folder permissions. For example, you can grant users the Traverse permission for the Test folder in the shared folder area. Then, they can access items embedded in dashboards stored in this folder. Also, they can access embedded items in dashboards stored in subfolders, such as /<shared folder area>/Test/Guest folder. However, users can’t access (meaning view, expand, or browse) the folder and subfolders from the Catalog.
7. Click OK twice.

Hope it helps!