vCard will not allow standard user access

Hi,

We are trying to use the vCard module on a Drupal site, it works fine for the Admin user however a normal user gets a Drupal "Access Denied" page when they try to download a vCard. We have checked the appropriate permissions for normal user and tried rebuilding the permissions/running update.php with no luck. Could someone point me in the right direction as to how I can dig deeper into this to find a resolution?

Kind Regards
James