strings and arrays

when I use the first myArray below this macro outputs a message box that tells me all the values I put into the array, however when I try to read some strings into the array from range A14 to A21 (sheetnames to look for), the code errors at the line: msgString = msgString & myArray(z) & vbCrLf

Sub arry()

 Dim myArray As Variant
 Dim msgString As String
 Dim z As Long

 Worksheets("Controls").Activate

 myArray = Array(32, 39, 56, 57, 71, 90, 107, 134)
 'myArray = Range("A14:A21")

 
 For z = LBound(myArray) To UBound(myArray)

  msgString = msgString & myArray(z) & vbCrLf

 Next z

 MsgBox "the values of my array are: " & vbCrLf & msgString

End Sub