What causes **** Invalid Keyword *** in the Index Tab?

Greetings fellow RoboHelpers,

Somewhat minor issue, but I'm curious if anyone knows the cause and the fix.

System Info:

• We're using the latest RH 9.
• Html Help (chm) output.
• Windows 7 64-bit OS for English, Chinese was compiled on Windows Vista 32-bit OS.

The Problem:

I'm getting this error in the Index tab when I view our Chinese-localized help project.

If I click on this keyword it opens up a topic.

The topic has these keywords:

I copied and pasted each of these into the chm's Index tab, and from what I can tell, the ones I marked in yellow in the image above aren't showing up in the index. So I assume it's one of those. But I'm not sure what's causing it or how to fix it.

I did a Google search on these phrases and it's curious that there's really there's not much out there on this:

chm "invalid keyword" "Index tab"

"html help" "invalid keyword" "Index tab"

I suspect there's something odd with the Chinese characters that's causing this issue. Any ideas?