When it rains it pours! Sorry for all the questions!

When I go into certain customer's orders, I get an error saying 'Invalid rate type in customer's accoutn set ACCTUS'. ACCTUS is just our US accounts.

I checked that control account, and it's default is set to 'ME'. The company profile is also set to 'ME', and 'ME' has been set up in Multi-Currency.

What's going on here?

Thanks!