i created 2 erlang nodes in the same Windows machine with two cmd windows:'unclient@MYPC' and 'unserveur@MYPC' , the server code is very simple :

-module(serveur).
-export([start/0,recever/0,inverse/1]). 
%%%%
start() -> 
process_flag(trap_exit,true), 
Pid=spawn_link(serveur,recever,[]), 
register(ownServer, Pid). 
%%%%
recever() -> 
receive 
{From, X} ->From ! {ownServer,1/X} 
end. 
%%%%
inverse(X) -> 
ownServer!{self(), X}, 
receive 
{'EXIT',_, _} ->start(), 
                sorry;

{ownServer, Reply} ->Reply 
end.

so at the server node cmd i start this module

c(serveur). 
serveur:start().

and i tested this server :at the server node cmd i used :

apply(serveur,inverse,[2]).

and i received 0.5 and i tried too causing an error by using an atom in the place of a number :

apply(serveur,inverse,[a]).

and the shell shows the error and shows 'sorry' and the server returns to its work correctly by restarting his child automatically because it is a system process and he traps the exit of his child.
now at the client node i used the rpc call function to try the connection and all is fine, for example i try :

rpc:call('unserveur@MYPC' ,serveur,inverse,[2]).

and at the client node cmd i receive :0.5
now i use an atom to send it to the server for causing an error

rpc:call('unserveur@MYPC' ,serveur,inverse,[a]).

at the client cmd node : i waited for the response from the server that should be 'sorry' but i didn't receive anything and there is no more the client prompt :

unclient@MYPC 1>

i can write but the shell does not execute my instructions anymore and there is not any prompt. at the server node : i see an error and then the server prompt returns normally

unserveur@MYPC 5>

i tried this at the server node prompt :

apply(serveur, inverse, [2]).

and i had an error, so i restart the server manually by calling the start() function at the server node cmd and after that the server returns to work normally. I tried self() on the server node cmd before and after the client call and the pid is the same and this is logic because the main server process is a system process so my result that he didn't execute the code after receive {'EXIT',...}. why that happens ? i couldn't understand this bug so any one can explain to me please what that happens ?