In order to put or change an investor password, go to MT4 >> Tools >> Options >> Server and click the change button on the right, then in the window that opens put the master password of your account and below the investor password you want (first tick the: change investor (read only) password), then click OK.
They don't povide the investor password, you put it.
The error message your are getting is telling you that you don't put the correct master password in order to set an investor password.
You have it all wrong, you are probably logging every day with an investor password you've put long ago and you think that this investor password is your master password but it isn't.
That's what "not enough rights" mean!
New accounts in any broker, doesn't come with investor password pre-defined, you only as the owner of an account, can create an investor password.
So, the workaround is this, go to the members area of your broker and reset your master password, if you can't do it, the support (or live chat) can do it and they will email the new master password to your email.
Then you can change this master password or set a new investor password with the way I've described on my previous post.
If I was logging in with an investor password every day, then I wouldn't be able to execute any trades. But I execute trades every day, so I can only be logging in with my master password.
Also, I did contact customer support about this problem, and their response was that they don't support investor passwords.
Try to reset your master password (in the members area of your broker) and then set an investor password, there is no other way around this.