Or try the "what you propose is impossible" forum.
By policy no web application is able to run arbitrary code on a client computer, at least not without the use of a plug-in like ActiveX or a feature that installs with a given program. Just think if I could launch and pass arguments to regedit.exe from my web code! I could destroy your registry/computer! That would be huge trouble!
The best you can hope for is to serve a file that will open up in Quickbooks by default. This can be in the form of an attachment or in the form of a standalone document.
MCP, MCTS - .NET Framework 2.0 Web Applications