How can I convert a PowerPoint or OpenOffice presentation to video in C# on my server side? (ASP.net)

Question

I have a problem by converting a powerpoint presentation to video.

I know that I can use the interrop library but my problem is that office can not be stable on an application server side (see: http://support.microsoft.com/kb/257757)

Application ppApp = new Microsoft.Office.Interop.PowerPoint.Application();
Microsoft.Office.Interop.PowerPoint.Presentations oPresSet = Presentations;
Microsoft.Office.Interop.PowerPoint._Presentation oPres = Open(OriginalFile,MsoTriState.msoFalse, MsoTriState.msoTrue, MsoTriState.msoFalse);
try
{
    oPres.CreateVideo(exportName);
    oPres.SaveAs(String.Format(exportPath, exportName),PpSaveAsFileType.ppSaveAsWMV, MsoTriState.msoCTrue);
    waitingForPowerPointConversion(oPres);
}

How can I do if I want to allow my website to convert a powerpoint uploaded by the user in video by my server?

Thanks for help