The line that does the include is "Net::IRCService". That instructs Perl to look for a "IRCService.pm" file in the directory "Net". It looks for this directory in any of the paths in @INC. However, if this file cannot be found it will error out as shown.
If he explicitly included the file instead of the module, or he added the correct path to @INC there shouldn't be a problem. If he doesn't have the file, it shouldn't be too hard to download it.