cannot create excel through ASP.NET

[Kumar@discussions.microsoft.com MPL Kumar]

I am using Microsoft.Office.Interop.Excel 12.0 to generate an xl file at the
server(win 2003),add some sheets of data and download it to client.But it
throws me an exception when I add sheets to workbook .

_Workbook workbook = workbooks.Add(XlWBATemplate.xlWBATWorksheet);

The exception message is as follows.
Microsoft Office Excel cannot open or save any more documents because there
is not enough available memory or disk space. • To make more memory
available, close workbooks or programs you no longer need. • To free disk
space, delete files you no longer need from the disk you are saving to.

Help Please.