I have created a font in Arabic but using an existing Arabic font in FL5 I replaced all the characters with the new font but using the same glyph window and character base. But when I try to generate as OTF and install the font the characters do not type the way it is supposed to. I really need help/or step by step if any options need to be used to generate it correctly.

Problems encountered
1.

<XXXXXXX> The feature file OS/2 overrides TypoAscender and TypoDescender do not sum to the font em-square.

2. Screen Shot showing the issue of misplacement.

1: Ascender and Descender from most important font dimensions should sum to your UPM (1000?)
2: FontLab can not make or decompile OT features that are needed to make Arabic work well. You need to use Volt, where you can build anything with some effort, or use Glyphs, which does basic Arabic things for you.