After installing 7.1 I cant run it, because it says something like "trial period expired" and asks me for product code / serial number and Password.
The first two I have, but no password.
When I go back to 7.0.3 it just asks for Product code during installation and then it runs.

this true for me, too. it works if i install into the existing 7.1 beta directory. installing into the old 7.0.3 directory fails with the behavior described by til.

If you look at the download-page, you 'll find the requested password. ;-)

Password for http://www.allroundautomations.com/registered/plsqldev.html ?
This doesn't work for me. :-(

I dont see a password on the download page and the download password does not work for installation.

@til you'll have to send an email to support to get the password (at least I had to). A workaround though:

Install 7.1rc1 into the target directory. This will let you enter registration information without password. Next install 7.1 final over rc1. This worked for me.

Thx.