Hi there !
I read on some walkthrough that if you entered in Commander Ralph private quarters, so that he would come and close the door, you would block some very important quest forever ?
I don't even know which quest (I just read the "tips" part of walkthrough), so I don t know if that is true, but do you have any information on this or any way to go around ?
THanks !

Also - I read there was a 1.4 unofficial patch. Do anyone know where I can find it ? And if it breaks save ?

This post may be helpful concerning broken quests.
The current GOG version is V1.005A which is available by redownloading the setup.exe from your account. Look at the bottom right corner of the startup screen to see which version you are running. I can't tell you what the current version for a retail copy is . . . =)
Edit: If you are not running V1.005A, you should definitely download the patched version before playing. It fixes MANY problems. The GOG patched version will not break existing GOG saves, just backup before uninstalling the game and move the saves back into the new install.