How to check if a directory is existed?

[VitaminB6]

Follow code is part of my code to check every file's date in a directory, PathForTime, However, I found some of the subfolder may not contain "\ISIS\, and then I use IF Dir(myFileName2) <> "" to check if the subfolder exists. One error message shows up until "myFileName = Dir()". I wondered what was happened? My intention is to check if the subfolder, "ISIS", is in the directory or not? Can someone help me with this?

myFileName = Dir(PathForTime, 16)
Do While Len(myFileName) > 0
If Left(myFileName, 2) = "PE" Or Left(myFileName, 2) = "JE" Then
LotDateForSK = DateValue(FileDateTime(PathForTime & myFileName))

If LotDateForSK >= FromDateForTime And LotDateForSK <= ToDateForTime Then
myFileName2 = PathForTime & myFileName & "\ISIS\"
If Dir(myFileName2) <> "" Then
LotIDArray(LotIDTemp) = myFileName2
LotIDTemp = LotIDTemp + 1
End If
End If
End If
myFileName = Dir()
Loop

 

[VitaminB6]

I observed onething which is if ISIS folder does exist, no error message shows up, however, we get an error message as the ISIS subfolder is not in the directory.
Can Anyone help?