### This is the the problem area ###
   @vacation_str=$telnet->cmd("$SED s/\$SUBJECT/SUBJECT/g /home/$username/.vacation.msg");   
   ###

##</code><code>##

 ### This is the the problem area ###
   @vacation_str=$telnet->cmd("$SED s/\\\$SUBJECT/SUBJECT/g /home/$username/.vacation.msg");   
   ###

##</code><code>##

   @vacation = map { s/\$SUBJECT/SUBJECT/g }
               $telnet->cmd("cat ~$username/.vacation.msg");