Issue:

The Opportunity named "[OpportunityName]" does not have an Account. Please add an Account to the opportunity in Salesforce.com and synch again.

Why It Occurs:

There is no Account specified in the Account Name field in the Opportunity. Since QuickBooks requires a Customer to be associated with a Transaction, DataSynch follows the same principles.

Resolution:

Enter an Account Name into the Account Name field in the Opportunity.