"An Error Has Occurred!
You are not allowed to send personal messages. "
that's quite annoying ;D
See: http://forum.simutrans.com/index.php?topic=4452.0
If it's related with the PM I've sent you, gauthier, send me the reply by email or leave a comment in the irc channel and I'll check it later at the log.. :)
I just understood that only moderator can send PM :D
You should let the PM sending for known members ... :-[