What is this ITIRCL.dll not registered error?
The itircl.dll errors are happening because (for reasons unknown) the ITIRCL.DLL didn't get registered properly when you installed the MS HTML Help workshop. You should be able to fix that by running these commands from a console window.
The paths may be different depending on where these DLLs live on your machine:
regsvr32 "C:\Program Files\HTML Help Workshop\itcc.dll"
there is more info here: http://frogleg.mvps.org/helptechnologies/htmlhelp/hhtips.html#hhc6003