A form is displayed with invalid characters
You may have different codesets on the development machine and the production server.
The typical mistake that can happen is the following: You have edited and compiled a form-file on your Windows® development workstation with the CP1253 encoding; When using the .42f form-file on a UNIX-server with encoding ISO-8859-7, invalid characters will appear.
Keep in mind that all source files must be created/edited in the encoding of the server (where fglcomp and fglrun will be executed). Consider writing your sources in pure ASCII-7, and put language/codeset specific messages in localized strings.