K8090 on Win7

I bought a K8090 a few years ago and wrote a few programs for it in VB 2008 on a Windows XP computer. Now i want to transfer them to a Windows 7 (64 bit) computer and work on them with VB 2010. I installed the relay card, it is working perfectly with the Demo, also added the Velleman.Kits.dll to Visual Basic but every time i try to run the programs,through exe or VB, and connect them to the card, they crash:

************** Exception Text **************
System.DllNotFoundException: Unable to load DLL ‘K8090D.dll’: The specified module could not be found. (Exception from HRESULT: 0x8007007E)
at Velleman.Kits.K8090Native.OpenDevice(String szPort)
at Velleman.Kits.K8090Board.Connect()
at Relay_v1._0.MainForm.Button2_Click(Object sender, EventArgs e) in C:\Documents and Settings\zoli\My Documents\Visual Studio 2008\Projects\Relay v1.0\Relay v1.0\Form1.vb:line 5
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

What can be the problem?

Search on how to build your project in x86 mode (32-bit). Your applications are now probably 64-bit, while the DLL remains 32-bit = incompatible.