APEX

Greetings!

I want to populate a table with values partially from another table (1:1-relationship) with an INSERT ALL INTO-Statement:

INSERT ALL INTO
tbl_MAuthentifizierung (id_mitgl, logname) values (id_mitgl, "name", 'schach')
SELECT id_mitgl, substr(vorname,1,2)||substr(nachname,1,3) "name"
FROM TBL_MITGLIEDER;

Now, when I run this statement in SQL-Developer (on another schema), it works. But when I try to run in in APEX-SQL-Workshop (v 4.1.1) in the command-line, I get the error-message:

'ORA-00942: table or view does not exist'

... although I copied the names over from the Object-Browser.

How can I solve this?

I could do this in SQL-Developer, however I have another promlem here, which I hope you could help me with, too:
For my new project I set up a new workspace in APEX. Now I can't set up a conection to that from SQL-Developer... (I'm still quite new to all of this)
In the dialog for a new connection, as I understand, the connection-name you can select yourself, then I'm getting insecure: the username is the name of the scheme, and the password is the password, you asigned to the APEX-workspace-developer? Or which one? Because, when I want to set up a new connection there, I always get the error-message:
ORA-01017: invalid user/password; logon denied

Thanks in advance for your help, with best regards
Tobi