Much simpler ( and faster !):

sub snb()
  c00="D:\My documents\xyz\"
  c01=dir(c00 & "*.csv")

  do until c01=""
    open c00 & c01 for input as #1
      sn=filter(split(Input(LOF(1),1),vbcrlf),"filtercriterion")
    close
    c01=Dir
  loop
End Sub
sn is a 0-dimensional array containing all 'rows' in the csv-file that contain the searched for textstring.

You can even add the content of all csv files into 1 string before splitting and filtering.