Here is a quote from the CVi documentation: 
LaunchExecutable 
int LaunchExecutable (char filename[]); 
Purpose 
Starts running a program and returns without waiting for the program to exit. 
 Note   If you want to wait for the program to exit, use the system function in the ANSI C Library. 
The program must be an actual executable; that is, you cannot launch commands intrinsic to a command interpreter. 
The executable can be either a DOS or Windows executable, including *.exe, *.com, *.bat, and *.pif files. 
.exe, .com, and .bat DOS programs use the settings in _default.pif (in the Windows directory) when running. You can change their priority, display options, and so on., by editing _default.pif or by creating another .pif file. Refer to www.msdn.com for information about creating and editing .pif files. 
If you need to execute a command built into command.com such as copy, dir, and others, you can call LaunchExecutable with the following command: 
command.com /C DosCommand args 
where DosCommand is the shell command you want to execute. For example, the following command string copies file.tmp from the temp directory to the tmp directory: 
command.com /C copy c:\\temp\\file.tmp c:\\tmp 
 Note	If you want to monitor whether the launched executable has terminated, use LaunchExecutableEx. 
In other words: It should work...