It seems to want me to rename the Requirement Types in my project before it will recognize the Type during "export".
For example, upon export, I kept getting the error:
"Requirement Type 'Business' does not exist in the requirement type lookup list."
I had the requirement type "Business", which I think is a default type. In Project Customizations, I had to rename "Business" to "Business Requirement". Then Import the requirement types using the Word QC Macro. Then I could successfully export the requirements without getting that error.
Then later I was getting the same error with other requirement types. I found that if I imported the requirement types from my project right before exporting to QC, the errors went away.
Very strange. I'm on Windows 7 with Office 2007 and an outdated QC version; so maybe that's why.