As nobody seems to have the answer, i am glad to tell that i finally
found the problem.
First, i observe that it was a OS-related problem, not a perl-related
problem.
For instance, with the last version of PHP, the following command did
not produce the correct result (in this case, it should print "6") :
<> echo "<?php print getprotobyname('tcp'); ?>" | php
The fact was that some internet-programs like the google desktop search
bar or spywares destroy some reg keys corresponding to Winsock (ie the
TCP/IP stack of Windows).
As nobody seems to notice the relationship between the two, and as this
"bug" could rot the life of somebody else, i prefer to include the
solution which helped me.
See (in french) :
http://forum.hardware.fr/hardwarefr/...t-222384-1.htm
To be short, rename
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Servic es\WinSock and
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Servic es\WinSock2, and
desinstall/reinstall TCP/IP in the properties of your network card.
Solution also cross-posted there =>
http://bugs.activestate.com/show_bug.cgi?id=44288
As I firstly think it was a Perl-bug.