Question Accessing dll

[mukul2k5]

Hi, I had an application written using vb 6.0 i converted it into vb.net 3.5 framework. In this application i use to pass a structre by ref to dll which is written in vc ++ (unmanaged code). when i run the program i use to get the following error

Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

A first chance exception of type 'System.AccessViolationException' occurred in ABC.exe

now here is a code snippet how i am calling this function

Public Declare Function RunCommSpec1 Lib "XYZ.dll" Alias "CDE" (ByRef ASD As HTY, ByRef dataStruct As RET) As Byte

the DLL is in bin directory

I can not understand why i am getting this error. i worked almost a week for this error.

Thanks