The first things I'd check are:
Are CAL's assigned to the document and have you specified the Usernames or checked 'Allow Dynamic CAL Assignment' in the Manamgement Console.
Are the security permissions of the folder where the .qvw resides setup correctly to allow you're username access.
If you're accessing via the Client is it licensed directly or does it need to first lease a license.
Hope one of those helps...but I have a feeling it won't - it sounds a more complex issue.
All the best,
Matt - Visual Analytics Ltd
Qlikview Design Blog: http://QVDesign.wordpress.com