Oracle SQL Developer - Data Miner Repo - Task failed - oracle

Question

I've been fighting against oracle sql developer for about two days and I just can't get the thing to work.
I would like to learn more about data mining and take a look at their examples and work threw their tutorials, but I cant even get the thing setup.
What I did:
Installed Oracle 12_1 database + oracle_examples.
I then created an administrator account via the oracle sql developer.
connection name: admin
username: sys
password: password
Role: sysdba
SID: orcl
Everything else was left as it is.
I then had to install all the example .sql files manually.
I followed the guide from here: Oracle Install Example Schemas
I did everything exactly the same as the guide told me to do, except I had to do this "hack" command which allowed me to create users. Else I would always get the
ORA-65096: invalid common user or role name
alter session set "_oracle_script"=true;
The new users now show up in every connection that I create in my SQL Developer under "other users". (HR, OE, etc..)
Now I created a new user "dmuser" like the guide told me to do here: (yes - with sql plus)
Oracle create a datamining user
Now I wanted to install the data miner repo. Which should be very easy:
Tools, data miner, make visible. And the data miner window showed up. I then added my dmuser connection, double click dmuser to install the data miner repository. I then press start to install the repo and then it says "Task Failed" with the MOST useless error message I have ever seen:
anonymous block completed
anonymous block completed
Drop public synonyms created by ODMRSYS.
anonymous block completed
anonymous block completed Total Number of Objects: 0
Total Number of Objects Dropped: 0
Total Number of Objects Failed to Drop: 0
Can anyone help me resolve this issue? My guess would be that the "hack" command which I used to create all the users messed something up, but I'm not sure. I'm very new to Oracle, so I have no idea what I'm actually doing here, so please have some mercy on me.
Thanks in advance.
Hope someone can fix this mess.

Answer 1

Aight, be prepared for a complicated answer...
Sql developer exectues a .sql file to install the data miner repo.
The sql is named "installodmr.sql". Found the info here:
Install repo by script
I had a look at the script and what it does. It opens more scripts which insert tables, and users and grant privileges etc...
The problem why the script would not execute correctly was due to a couple of reasons.
1) As mentioned in my question, I can't just create a user, I have to type the command:
alter session set "_oracle_script"=true
The script calls other scripts that then want to create user, which in my case was not allowed and caused the ORA-65096 error.
So I had to insert the alter ... command before the script called another .sql file.
2) The path to the .sql files was not correctly set and it could not find the files which caused problems. They where referenced like this:
##file.sql
I changed it to the direct path:
#C:\Oracle\product\12.1.0\home\sqldeveloper\dataminer\scripts\file.sql
I let the script run and it worked.
Now data miner repo is installed.
Wuhey! :)