Is the Inventory Server service running on your core server?
Make sure that it is running and that there is a valid entry in the inventory for the computer you are targeting.
Here is a document that will likely help you in troubleshooting this.
http://community.landesk.com/support/docs/DOC-6747
This also can have to do with permissions.
If you have an Administrator account, it will use the Administrator account without further questions.
However, if it is a non-administrator account, it will look at the RBA (Role-based administration) rights.
If not logging in as a full administrator (LANDesk Administrator), you will need to ensure you have the proper RBA rights set for that user.
I hope this helps.
Also, if you do a search in Google as "site:community.landesk.com retry 40 of 40" it will pull up a lot of discussion and information about this.
