Hi Xavier,
It sounds like the <load_module>.bat file is locked by another process, which if the previous build finished successfully or otherwise should not be the build tool javaw.exe process itself.
You could install Process Explorer to see if you can find which process is holding the .bat file handle: Process Explorer - Windows Sysinternals | Microsoft Docs
Note when Build Tool javaw.exe is executing the .bat file typically you won't see that file under the file handle list of the javaw.exe because only the commands being run by the .bat will be listed.
If you run the Build Tool Clean option it should be able to remove the .bat file.
I am wondering if you have anti-virus software installed which could be locking the .bat file?
I hope that information helps.
Regards,
Lynn