• I did notice if you mentioned this but make sure the file you are writing to has Read and Write on it. (gbook.txt). If you do a chmod 755 on the script it will only give the Internet user RX rights to it.
  
  
• Also run your script with a -w where it says #!/usr/bin/perl -w and run it from the command line. Then it will show you any errors that it has with anything that you have done in the system.
  
  
• Try using the CGI.pm (or CGILite.pm)module to get the information that has been posted/sent by the HTML document. Using a module will clean up your code and make it more understandable to debug.

--BigJoe

PS I actually tried to bring up gbook.txt as it shows in your script and there is none accessable to the Internet User in that location.