A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
I have found the solution:
My code uses Office 2003 Web components.
As long as I had Office 2003 installed on all machines, all relevant components were already there.
Once I uninstalled Offices 2003 and installed Office 2010, all those components were also removed
so my application has failed to load them.
The solution is simple:
Download and install Office 2003 Add-in: Office Web Components on all relevant machines
This way relevant components are back on your machine(s) and the application can use them again.
Enjoy