Data refresh on dashboard when excel file is data source

Question

Hi, can anyone help?

Is it possible to have this kind of scenario on MOSS 2007.

I have one EXCEL workbook in doc library in which users insert and edit table data. I would like to have another workbook in which I would create pivot table and chart summarizing data from first file and I would like to display this report by excel web services on a dashboard page, but would also like to have automatic refresh of data on this dashboard.

In every kind of solution I get unable to refresh data error.

Please give me some advice on what should be done to have data refresh on dashboard when excel file is data source.

Thanks in advance.