Ok, Saran-
I verified the quirk you described (Control Panel showing at top of FILE MANAGER page for non-page-editor roles) and have one method of getting around it.  I've updated my original blog posting with an optional step #7 which I'll repost here:
 

7. (THIS STEP IS OPTIONAL) One quirk with this is that those who get "EDIT" rights to the FILE ADMIN module will also end up getting a partial CONTROL PANEL display (the admin/page editor bar across the top of the page, above the skin).  This is unnecessary and potentially confusing.  It doesn't hurt anything, but if you'd prefer it to not appear you can add the following lines to the very bottom of your DNN skin file (sorry - this won't work from inside a Text/HTML module or from within a page's Header Tags setting).  Note that if you copy-and-paste this code directly you'll need to remove the extra space just after each "<" and just before each">":
 
< % If Not DotNetNuke.Security.PortalSecurity.IsInRoles(PortalSettings.AdministratorRoleName) % >
   < style >.ControlPanel{display:none}< /style >
< %  End If  % >
 
You'll need to add additional checks for any page-editor roles you've created.  For instance, if you created a page-editor role named "Editor" you'd use the following:

< % If Not (DotNetNuke.Security.PortalSecurity.IsInRoles(PortalSettings.AdministratorRoleName) OR
            DotNetNuke.Security.PortalSecurity.IsInRoles("Editor")) % >
   < style >.ControlPanel{display:none}< /style >
< %  End If  % >
 

Please note that this will hide any HTML element using the CSS class "ControlPanel".  If you really want to be safe and confine this change to the File Manager page you should create a second copy of your skin's .ASCX file (just rename the copied ascx and place it in the same directory as the original), add the code above and apply the renamed skin to the File Manager page.
 
 
-mamlin