Using TINV function in C#

[Matt Bailey]

Good day,

I was wondering if anyone could explain to me why I am getting this
error:

Retrieving the COM class factory for component with CLSID
{00024500-0000-0000-C000-000000000046} failed due to the following
error: 80070005

I am attempting to call Excel's TINV function from C# with the
following code in VS.NET 2005 (using ASP.NET 2.0):

Excel.Application app = new Excel.Application();
Excel.Workbook book = app.Workbooks.Add(filename);
double t = book.Application.WorksheetFunction.TInv(prob, df);

a) Is there a problem with how I am connecting to the spreadsheet?
b) Is there a permissions issue with ASP.NET?
c) Can I use the 'Missing.value' from the System.Reflection namespace
in place of the filename?
d) Is there another way to gain access to the TINV function besides 3rd
party software?

Anything I have found up till now on the internet on this subject has
been of little use.

Any and all help is greatly appreciated