The trial balance usually summarizes the information stated in the General Ledger. If the general ledger has problems, you may be having much more problems in tracking the error as you summarize it in the Trial Balance.. Here are some:
1. Transposition Error - the error in posting whereby instead of posting 9,093, you misposted it as 9,903. This error is easy to detect because all transposition errors are divisible by "9".
2. Misposting into another account - instead of posting it to Accounts Receivable, you posted it into Accounts Payable. - This will render both accounts MISSTATED.
3. No postings made - the type of error that will put the Trial balance into "balance" but accounts are also misstated because of omission of a certain transaction.
There are others, just think that the source of trial balance is the general ledger. So basically, the root of all the problem MAY come from inaccurate postings from the journal to the ledger..
Good Luck and Have an Nice Day!