I have a program using API calls for the common dialog functions, but have run into a minor issue with one of my users who runs the program on Wine. (Linux)

Here's how I load up the structure that I send to the API:

Code:
Private Function GetStructure(pstrPath As String, pstrFile As String, pstrFilter As String, pstrDefaultExt As String, penFlags As FlagsEnum) As OPENFILENAME
    Const OFN_FILEMUSTEXIST = &H1000
    Const OFN_PATHMUSTEXIST = &H800
    Const OFN_HIDEREADONLY = &H4
    Const OFN_LONGNAMES = &H200000
    Const OFN_OVERWRITEPROMPT = &H2
    Const OF_WRITE = &H1
    Const MAX_PATH = 260

    With GetStructure
        .lStructSize = Len(GetStructure)
        .hwndOwner = Screen.ActiveForm.hwnd
        .hInstance = App.hInstance
        .lpstrFilter = Replace(pstrFilter, "|", Chr(0)) & Chr(0)
        .nMaxFile = MAX_PATH + 1
        .nMaxFileTitle = MAX_PATH + 1
        .lpstrFileTitle = Space(MAX_PATH)
        .lpstrInitialDir = pstrPath
        .lpstrDefExt = pstrDefaultExt
        Select Case penFlags
            Case feOpen
                .lpstrTitle = "Open"
                .lpstrFile = Space(MAX_PATH)
                .flags = OFN_FILEMUSTEXIST + OFN_HIDEREADONLY + OFN_LONGNAMES
            Case feSaveAs
                .lpstrTitle = "Save As"
                .lpstrFile = pstrFile & Space$(MAX_PATH - Len(pstrFile))
                .flags = OFN_PATHMUSTEXIST + OFN_HIDEREADONLY + OFN_LONGNAMES + OF_WRITE ' + OFN_OVERWRITEPROMPT
        End Select
    End With
End Function
Then I handle the return value as follows:
Code:
ShowSaveAsDialog = Left$(typFileName.lpstrFile, InStr(typFileName.lpstrFile, Chr$(0)) - 1)
This works great in Windows, but for the guy running Wine, he's getting the full 260 characters in his save dialog default filename. If he just clicks the Save button without doing anything, the program crashes with a stack dump termination.

My question:

Can I change the MAX_PATH values in the structure part to be the length of the string, or will that cause problems in Windows if the user chooses a longer filename (or path) than what I'm putting there as a default?