I read it a few times, in English and in Dutch. Here is a list of differences between the English and the Dutch versions:
 
 

English	Dutch
Earth is destructed on Thursday	Earth is destructed on Wednesday. In the fourth book, this is again replaced by Thursday
The planet of the robots is called Krikkit	The planet is called Hokkie (Hockey). In the fourth book, this is again replaced by Krikkit
"Ford Prefect"	"Amro Bank" (a largish bank in The Netherlands)
"Slartibartfast"	"Magdiragdag"
... use of the word "Fuck" ...	... gebruik van het woord "Kut" ... (Cunt in English)