Logical field in query by form

A query launched via pushbutton from a form reads (shortened below)

It functions perfectly until it begins to parse the logical fields which are activated by check boxes on the form. The check boxes have the values "TRUE" and " " (void)

The syntax error is "error incompatible types"  How would the parameters for a logical field read?

Identifying stExec as  String  reports that there is no field "False" in mainrol.db. I must have missed one check box when I altered the unchecked value to void, but it is passing the value as the field name.

Changing the input to a labeled field (enter "TRUE") will probably work, but I'd like to know how to handle a logical field. Any thoughts appreciaated.

method pushButton(var eventInfo Event)

var
  stNAME                            String
 stExec                            Logical

  quQuery                           Query
  tvResults                         tableView

endvar

stName = fldname'value

stExec = fldExec'Value

    if StNAME.isBlank() then
        StNAME = "Check"
    else
        StNAME = "Check " + StNAME
    endif

    if stExec.isBlank() then
        stExec  = "Check"
    else
        stExec  = "Check " + StNAME
    endif

Query

ANSWER: :WORK:Results.db

mainrol.db | Name      | Exec |

                        | ~stName |  ~stExec |

endquery

errorTrapOnWarnings(Yes)
quQuery.writeQBE(":Work:SearchQuery.QBE")
try
    quQuery.executeQBE()
    tvResults.open(":WORK:results.DB")
tvResults.wait()
tvResults.close()
onFail
errorShow()
    msgStop("", "")
endTry
errorTrapOnWarnings(No)

  endMethod

Answer to self:

1) Declaring as string worked for a bit. Now not passing value to the query. 

2) The negative value on the query form must be blank. If set to False, only those records with the value false in the logical field will be called up. The checked  value remains TRUE (Or yes, whatever is desired