You might just want to save the state of your program to a file and re-spawn a new copy of self with this new data. Consider:

        if (ClassFileChanged())
        {
              my ($state_file) = SaveToStateFile();

              if (!RespawnFromStateFile($state_file))  # I.E. 0 == no 
+error
              {
                     exit(0);
              }
              else
              {
                     warn "Could not reload $0 properly.\n";
              }
        }
[download]

This will prevent you from crashing your program if you break your class file (i.e. typo, compile error, etc.) and it will give you a chance to fix it properly.

Of course, if you're inside of mod_perl, calling exit(0) will be futile, since mod_perl doesn't care about that sort of stuff and will just call the same program again for the next request.