I'm trying to convert an unmanaged C struct into VB.NET structure. No matter what I try I am getting the error...

Cannot marshal 'parameter #1': Invalid managed/unmanaged type combination (this value type must be paired with Struct).

Any help that you can provide is greatly appreciated.

Here is the C struct...

'/*****************************************************************************/
'/*   Parameter list for z4geterror()                                         */
'/*   NOTE:  Only fields containing +1 in the length are null terminated.     */
'/*****************************************************************************/
'typedef struct tagError
'{
'    int  iErrorCode;              /* Error Code                              */
'    char strErrorMessage[100+1];  /* Error Message                           */
'    int  iFileCode;               /* File Code                               */
'    char strFileName[26+1];       /* File Name                               */
'    char strDiagnostics[300+1];   /* Diagnostic Message                      */
'} Z4_ERROR;

I have tried this but it doesn't work...

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
Public Structure Z4_ERROR
    Public iErrorCode As Int32
    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=101)> Public strErrorMessage As String
    Public iFileCode As Int32
    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=27)> Public strFileName As String
    <MarshalAs(UnmanagedType.ByValTStr, sizeconst:=301)> Public strDiagnostics As String
End Structure

I have also tried this...

<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
Public Structure Z4_ERROR
    <MarshalAs(UnmanagedType.I4)> Public iErrorCode As Int32
    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=101)> Public strErrorMessage As String
    <MarshalAs(UnmanagedType.I4)> Public iFileCode As Int32
    <MarshalAs(UnmanagedType.ByValTStr, SizeConst:=27)> Public strFileName As String
    <MarshalAs(UnmanagedType.ByValTStr, sizeconst:=301)> Public strDiagnostics As String
End Structure