SQLiteDatabase locked after any insert "SQLiteCantOpenDatabaseException: unable to open database file (code 14)"

As i changed the android version and the path from externalsd to the default database-folder, i don't know where the error come from. I found that the reason might be problems accessing the journal file is locked (it is created by the programm).

the "test" is reading data and if it exists it updates and if not it inserts. This is done in a loop while reading lines from a file. For testing purpose i simplified it but the error is the same.

package ...;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
public class test {
    public test(SQLiteDatabase MyDB)
    {
        MyDB.execSQL("CREATE TABLE IF NOT EXISTS testtable (mytext TEXT, number INT PRIMARY KEY)", new String[] {});
        for (int i = 1; i < 5; i++)
        {
            String[] ColArray = { "any text", String.valueOf(i) };
            Cursor readCursor = MyDB.rawQuery("SELECT mytext FROM testtable WHERE number=?", new String[] { String.valueOf(i) });
            if (!readCursor.moveToNext()) // Error when executing moveToNext
/*
    In the 2nd time it runs over this point an Error occurs:
    android.database.sqlite.SQLiteCantOpenDatabaseException: unable to open database file (code 14)
    I need to remove the journal file to be able to connect to the database it again - the change made by the Insert/Update is successfully saved!
*/          {
                readCursor.close();
                MyDB.execSQL("INSERT INTO testtable (mytext, number) VALUES(?, ?)", ColArray);
            }
            else {
                readCursor.close();
                MyDB.execSQL("UPDATE testtable SET mytext=? WHERE number=?", ColArray);
            }
        }
    }
}

MyDB is a valid DB-Connection. 1) The Table is created 2) The Table is READ but Line 1 is not found 2a) READ again is possible until now if the read is closed. 3) Line 1 is INSERTED 4) when trying to READ again (the line 2 would not be found, too), moving the cursor fails.

The journalfile need to be deleted manually or the app will fail to start again when trying to connect.

Please Help! Thank you.