Looking at your data, I can see following issues where it could go wrong and display that message:
1) Do you have commas (,) in the csv file? Try opening your csv file in notepad.
2) 'Journal type' field for ex-accounts should have one of these: "Payments", "Receipts", "Sales", "Purchases", or "General"
3) 'Reference' number should be same for a debit-credit pair of transaction.
4) Check and match date format settings in Options -> Regional (,and also system date in Control Panel, regions and languages.)
5) Check 'Charts of Accounts' to see if account numbers 6900 and 1100 exist.
6) When importing, start from row 2
Your csv file in notepad editor should look something like:
"DATE","Journal type","Reference","Description (Journal Memo)","Account number","Account Description","Debit amount","Credit amount"
"2013-10-02","General","GJ1","Journal Entry AC ADMIN FEE","6900","Bank Charges","48.77","-"
"2013-10-02","General","GJ1","Journal Entry AC ADMIN FEE","1100","HSBC","-","48.77"
Hope this helps!
