Failed attempt to build app inventor on local device

Open Source Development
1

I receive same error when I try to build the app inventor:

BUILD FAILED
C:\Users\AR_KO\My project\appinventor-sources\appinventor\build.xml:16: The following error occurred while executing this line:
C:\Users\AR_KO\My project\appinventor-sources\appinventor\build-common.xml:301: The following error occurred while executing this line:
C:\Users\AR_KO\My project\appinventor-sources\appinventor\blocklyeditor\build.xml:120: Java returned: 1

Here are the lines I ran:
PS C:\Users\AR_KO\My project> git clone https://github.com/YOUR_USER_NAME/appinventor-sources.git
fatal: destination path 'appinventor-sources' already exists and is not an empty directory.
PS C:\Users\AR_KO\My project> cd appinventor-sources
PS C:\Users\AR_KO\My project\appinventor-sources> git remote add upstream GitHub - mit-cml/appinventor-sources: MIT App Inventor Public Open Source
error: remote upstream already exists.
PS C:\Users\AR_KO\My project\appinventor-sources> git submodule update --init
PS C:\Users\AR_KO\My project\appinventor-sources> cd appinventor
PS C:\Users\AR_KO\My project\appinventor-sources\appinventor> ant MakeAuthKey
Buildfile: C:\Users\AR_KO\My project\appinventor-sources\appinventor\build.xml

MakeAuthKey:

init:
[mkdir] Created dir: C:\Users\AR_KO\My project\appinventor-sources\appinventor\build\appengine
[mkdir] Created dir: C:\Users\AR_KO\My project\appinventor-sources\appinventor\appengine\build
[mkdir] Created dir: C:\Users\AR_KO\My project\appinventor-sources\appinventor\appengine\build\classes
[mkdir] Created dir: C:\Users\AR_KO\My project\appinventor-sources\appinventor\appengine\reports
[mkdir] Created dir: C:\Users\AR_KO\My project\appinventor-sources\appinventor\appengine\reports\raw
[mkdir] Created dir: C:\Users\AR_KO\My project\appinventor-sources\appinventor\appengine\reports\html

CheckAuthKey:

MakeAuthKey:

BUILD SUCCESSFUL
Total time: 0 seconds
PS C:\Users\AR_KO\My project\appinventor-sources\appinventor> ant

so I have the line "git submodule update --init" (and I tried to "ant clean" and run again still not working). what could be another potential problem?
Thank you very much!