Robohelp v9 crashes when generating Webhelp from linked FM book

Hello Robohelp mavens!

My environment:  Win7, FM v10, Robohelp v9. (TCS v3)

I've linked an FM book (containing 90 files) to a blank Robohelp project. Whenever I try to generate Webhelp, Robohelp crashes at some point.

As part of debugging, I clean the FM book (removed unused Pgf/char formats, conditions, etc.). That did not help.

Any idea why Robohelp gives up in the middle?

Any input is highly appreciated!

My best regards,

Roman