> // use the full path to the table because there is no dbc
> 1)//return this.GetDataSet("SELECT * From c:\\gmgwin\\main\\arypat01.dbf WHERE custid = '" + tccustid + "'");

Just a quick guess, but try escaping out the single quotes:

return this.GetDataSet("SELECT * From c:\\gmgwin\\main\\arypat01.dbf WHERE custid = \'" + tccustid + "\'");