URI Scheme, launch program in its directory

Question

I have registered URI scheme for my app. When I open it with "Run.." or in browser, it runs in hosted directory. For ex. Ive opened url in webpage, program's working dir is in browser.

What I want? I want to run program test.exe located at

C:\data\test.exe

and to use dir.

C:\data

so it could use other data in relative path. so test.exe would access file .\file.txt without using absolute path

Hope I wrote it understandable, sorry for bad English.