关于dll创建的问题请教(40分)

这个dll是在VB里创建的：
dll的工程名为files32
类名为filesystem
定义的函数：
Public Function EnumFiles(ByRef dir As String) As String
Dim FO As FileSystemObject
Dim FD As Folder
Dim Result As String

On Error Resume Next
FO = New FileSystemObject
Set FD = FO.GetFolder(dir)
For Each thing In FD.Files
Result = Result &amp
thing.Name &amp
" "
Next

EnumFiles = Result
End Function

在一个新工程里引用该dll之后我是这样使用的：
dim fs as new files32.filesystem
dim str as string
str=fs.enumfiles("C:/")
可是str为空,函数没问题，我试过了，为什么会没有返回值？
我在Delphi里定义了该函数之后，运行时提示找不到enumfiles入口，是怎么回事？

转贴:
修改为:
Public Function EnumFiles(ByRef dir As String) As String
Dim objFSO As FileSystemObject
Dim objFolder As Folder
Dim objFile As File
Dim Result As String
'On Error Resume Next
Set objFSO = New FileSystemObject '要加上Set
Set objFolder = objFSO.GetFolder(dir)
For Each objFile In objFolder.Files
Result = Result &amp
objFile.Name &amp
" "
Next
Set objFSO = Nothing
EnumFiles = Result
End Function