Multiple comments here:
- There's no reason to use START, EXEs are native formats that Windows knows how to launch. START is used to modify how Windows launches an EXE when you need to modify this (I've never found a valid reason to do this in ConfigMgr). This isn't the source of your issue, but still can contribute to confusion and other issues.
- Also not your issue, but there's no reason to use a batch file for a single command-line. Just use that command-line directly in your program.
- That exit code is from the command line that you are running which in turn is coming from the EXE called in your batch file. What that means is up to the developer of the EXE and it may or may not conform to standard Windows/Win32 error codes. It's not common, but some developers use an exit code of 1 as a success -- as noted, this is non-standard and up to the developer, not ConfigMgr, Windows, or Microsoft. Thus, you need to troubleshoot why this EXE is returning the exit code which may involve telling the EXE to create a log file (which is also something the developer defines) or consult the developer's documentation.