The stray or ghost line typically appears near the top of the financial statement or above the first real row of data, but it can happen anywhere.  The unknown row is appearing because the row format has a line defined with no format type and no formula.  By default, FIMS assigns a format of GL and when it sees no formula it picks an arbitrary GL account and displays a balance for that row.  Frequently it is the last row in the Trial Balance that is displayed, but not always.

To fix the issue examine your row formatter and check to be sure that all rows have formats defined and for all GL formats there is something in the formula column.  Usually you will change the format to desc or delete the line.