If not all the papers respect the same dates of the beginning of the Star signs, is for a mistake or not?

No.  They're all approximations, and they are more correctly called Sun signs not star signs.  The Sun changes signs on approximately the same dates each year, but there are variables.  Different time zones produce different calendar dates.  1:00 AM in London, during the winter is 8:00 PM in New York the previous day.  On leap years there is an entire day difference from the year before.  I have in my files two birthdays on Feb 18 one has the Sun in Pisces the other in Aquarius.  

Since it is not the same time everywhere on earth, and the Sun doesn't change signs at the same time every year, the best a publication can do is give the approximate dates.

Your past questions seem basically the same. Longitude is a man made concept. Time zones are as well. They were created by the transportation industry, not astrology.

Once most nations had their own prime meridian, usually passing through the capital cities. An international agreement made Greenwich the final location. Though France kept using Paris until 1911.