I've come across this issue many times, dealing with multi-company multi-currency. Got it working by making the secondary currencies all match on the journals and accounts being used for an accounting entry (for one particular invoice). Then I tried adding my own bank account journals to send/receive payments in alternate currencies and came across the problem again, getting stuck now

it is trying to create Two or more journals under same account... So check wether you are allowing multi currency...

Refer this: Multi Currency

My problem got solve by checking the allow multicurrency in the accounting setting then automatically it will show the secondary currency in the account_id . Remove this one just to import the journal items. change the journal_id if possible.