If the following message is displayed within Salesforce, it indicates that the Salesforce User who is trying to creat an account in the Business Intelligence application has not been granted access via it's "Profile" user interface by your Salesforce System Administrator: 

In order to resolve this issue, please ask your Salesforce System Administrator to enable the affected User via the "Profile" section in the "Setup" settings:

Setup > Profile > Select Profile > Edit

Once you click "Edit" on the profile that needs access you will need to locate the "Administrative permissions" section and check "API Enabled"

Once the Salesforce User has had the "API Enabled" checked and the configuration saved the above messaging will no longer be displayed.