Hi Timo, and welcome to the Tiki Community!
> -Can Tiki have more tabs than the standard tabs article/talk/read/Edit/View history ?
Not by default in php/tpl scripts. You would need to edit your tpl's to extend it with new tabs etc. See http://dev.tiki.org/Hello+World
> -I want to create a page for each input in my database, is it possible to automate the creations of these pages?
Yes, but this requires advanced knowledge with the usage of Trackers.
> -Forms: is it possible to 'freeze' the model of forms so that noone except an administrator can t change it?
Yes, you have several ways to change permissions globally or per tracker, so that only mambers of a groups have certain permissions, and other groups have lower level of permissions, etc. See Permissions
> -Is it possible to 'freeze' a part of a page so that noone except an administrator can t change it?
Nope as such, but there are workarounds to get a similar behavior:
- Convert your ordered sections in a wiki page into a series or ordered wiki pages within the same "Wiki Structure", and refine permms with the page you want.
- Regardless of whether using structures or just different pages out of the same structure, you can create a main wiki page to work as a "master document" (in terminology of Office suites such as LibreOffice, MS Office, etc), and include the subdocuments (other wiki pages) inside. This way, you get the effect of a single wiki page showing the whole "book" thruogh the master document, while you can keep different edit permissions per wiki page included in the master document.