About a mistake information

Hi, my english is very poor ,hope that you can know my words.
There is a mistake information “Integer overflow” after I edit the chinese font and save the file, why? what is my mistake? Thank you very much!

Hard to tell what goes wrong with this little information, but it most likely is a bug.

What version of FontCreator are you using and what is font are you working on (and what did you change to it)?

The version number is “Fontcreator 5.5” download from HIGH-LOGIC web site, The operating system is “WINDOWS xp SP2”.the font is Chinese font, I has try many Chinese font , however, this information is show. I just to edit the Arabic numerals in this font.

Thank you !