A common cause of this error is when you are using account numbers instead of account name descriptions for any of your accounts in the QB setup in Camelot. Be sure you have text descriptions for your accounts instead of numbers.
Also, newer versions of QB do not like for your sales tax account to be named "Sales Tax Payable", so on the QuickBooks tab of the Company Setup screen in Camelot, be sure it is named something different, like just "Sales Tax".
Another possible reason is that you have QB setup that you do charge sales tax, but you do not have that option checked on the QuickBooks tab of the Misc/Setup > Company/Misc Info screen in Camelot. Be sure that option is checked if you ever have to charge sales tax.
