TC 3.5 trial - Robohelp fails to make printed documentation

When attempting to generate printed output, fails - says it can't find Word.

At first, I installed the Office 2010 x64 trial, and that didn't succeed.

In Word, File?options>trust center, enabled macros and access to the object model.

No difference.,

Went to RH Tools>Options, added Word to open .dot, .doc, .dotm, .docx

No difference.,

Then I read there were interop issues between 32 bit apps and 64 bit apps.

Uninstalled Office x64, installed Office x32. Same symptoms.

Uninstalled TCS

Control panel > Office>repair

Re-installed TCS

no change.

Re-checked Word's macro security settings, RH's .dot and .doc settings - those had stayed as I set them - is that a clue?

Installed Office 2003 Pro, re-installed TCS.

Robohelp still fails to produce printed doc, claims it can't find Word.

help?