Based on my tests, that's what WinRAR says if a file, opened from within an archive, is deleted (from the temporary location WinRAR extracts it to, to run it), so it sounds like, in both cases, the executable is getting deleted. The executable unexpectedly getting deleted sounds to me like a false-positive in your antivirus software, causing it to delete it.says: "Lucas Simpsons Hit & Run Launcher.exe will be compressed only after closing the application using it. Modifications will be lost if you close WinRAR before that "
According to VirusTotal, none of the antivirus software, it supports, currently considers version 1.24 of the Mod Launcher a virus:
What antivirus software do you use?