With the last version no possibility to select scanner and scan a document

no possibility to select source

It should be in menu Insert > Media > Scan. If it is not there, rename your user profile folder to get a new user profile. Then please try again.

What user Profile folder and how to get a new one ?

read here: https://wiki.documentfoundation.org/UserProfile

Changing user profile did not work for me on Windows 7-64bit. Even deleting all the LO files did not help. What worked for me was installing the 32bit version of LO (ver 5.4.1)