RE: Bank reconciliation posting error.
As described in the Error message; the "Statement Ending Balance" you've updated on the top should tally with the "Total Balance" shown below the "Bank Statement Lines", and the "Total Difference" must be zero. Also, you will not be able to post the bank statement, while there are unmatched bank statement lines. If your bank statement lines are not matched automatically, you should match them manually by selecting the respective entries in both "Bank Statement Lines" and "Bank Account Ledger Entries" and clicking "Match Manually" option on the ribbon. Ones all the Bank statement lines are matched, and the total difference is zero, you will be able to post the Bank rec.