Adjustment of trial balance for income statement item which don't actually exist

May I ask how to make an adjustment entry to trial balance for opening balance of £100 of admin expense (include in admin expense stated in income statement) which was not actually exist; when I make an adjustment to admin expenses and profit for the year in equity, it causes the statement of financial position imbalance?

The opening balance of £100 is not related to any general ledgers showing in the trial balance, the accountant just stated in income statement as expenses.

Thank you for your kindly help. I look forward to your reply.

Cheers

Tino