Hmmm...the thing with the logfile works. Thank you, my hero ;-)

But I cannot get my application.exe starting up in the background! Both

system("application.exe 2>&1 | logscript.bat &");
open3(NULL, ">&NULL", ">&NULL", "application.exe 2>&1 | logscript.bat 
+&");
[download]

wait for application.exe to be finished or terminated.

I'd be glad if someone would help me with this last piece of the puzzle.

Thorsten