RH9 Classic : search results displaying topic IDs instead of labels in CHM

Hello,

Despite all my searching (here and elsewhere online), I've been unable to figure out the why (and therefore the way to fix it) of my problem, so I turn to you hoping someone will be able to help...

We've been using RH9 Classic to create our help files in the WinHelp 4 format. We are now moving to the HtlmHelp format. To do that we've created a new project importing all the .BMP images and .RTF files (and .HH file for the IDs map) and then generated the help file.

At first glance everything seems to work perfectly even the contextual help from the app displays the right topic, but there's something strange when you try to search for a word (or select a word in the index associated with multiple topics) : the results show the topics' IDs instead of the titles !

Here are 3 screen captures demonstrating the access to the same topic, through the TOC, the Index and the Search tabs :

Any idea where that could come from ? (Of course, if more information are needed, I'll be more than happy to provide them !)