from a class object I receive
"System.NullReferenceException"
"Additional Information: Object reference not set to an instance of an
object."

// C#
[DllImport("assvcapi.dll", EntryPoint="ASSVC_FetchChildFolders",
CharSet=CharSet.Ansi, SetLastError=true)]
public static extern int ASSVC_FetchChildFolders(
[MarshalAs(UnmanagedType.LPStr)] string strUserId,
[MarshalAs(UnmanagedType.LPStr)] string strCabinetId,
[MarshalAs(UnmanagedType.LPStr)] string strFolderId,
out IntPtr lpChildFolders);

IntPtr lpAnchor = new IntPtr();
int iRet = ASSVC_FetchChildFolders("ASADMIN", "1P6JS58", "1P6JS58",
out lpAnchor);

/* The C function */
int WINAPI  ASSVC_FetchChildFolders(char *pszUserId,
char *pszCabinetId,
char *pszFolderId,
void **ppvFoldersAnchor)

This works when called from within a windows form.  Why doesn't it work
from a simple class.