minor bug fix - serial no. 240608

Two minor game bugs were fixed in this update.  

• A padlock on a particular lockbox is now fixed in place and cannot be picked up.
• An area of the river could not be traversed twice without leading to death.  Although the game is winnable with a 100% score, the automatic death here was unintentional and has been relaxed.
• Fixed a typo on a sign post.
• Modify a minor puzzle detail to avoid an accidental solution.
• Updated DOS frotz.exe to frotz254.zip - DJGPP frotz.exe exhibited a bug affecting game score when restoring.
  
  Note: Due to the design of the Infocom Z-Machine, existing save files will not work in this update.  Starting a new game is necessary if updating between game versions.
  
  Happy adventuring!