Thank you for your post.
It is possible the file is corrupt.
If you return to the [Standard FileMaker Menus] option, do the scripts appear normally? Are you able to access them all? Are any script steps missing and/or corrupt? If you print out the scripts, do all script steps appear normally? (You can print to PDF). Do you have multiple Custom Menus?
Close the file, pull down the File menu and select "Recover...". Select the file in question, and recover the file. Open the recovered file. Has anything changed?
The Recover command will try to fix a FileMaker file. It is not a cure-all, and there is a possibility that it cannot fix the corruption, but it may help. The best solution is to use a backup, but by the tone of your email, it appears you don't have a backup. The next best solution would be to re-create your database file, importing the field and data from the old file.
Let me know how your script information is displaying and if you are having any progress.
I discovered that it was not a corruption of the file or the File Menu. For a reason that it was not completely clear the script itself has something incompatible that was generated like 2 months ago (I checked several version using the time machine and all of them had the same problem). The only thing that I can think of is that I changed some of the field used in the scripts to Global. So I rewrote the scripts and everything was corrected. The funny thing is that with the "corrupted" script after closing the window indicating that the script was not found or was deleted, the script was kicking in even if the name in the menu was blank (I forgot to mention that before).
Thanks for your help