The whtopic.js file is used only in topics. It contains all manner of functions for sending calls to the TOC, traversing browse sequences, etc.
The obvious question is: If you use the vanilla whtbar.js, does it work correctly then? In your earlier post you mentioned that you've made changes to the RH10 whtbar.js file. Was amending the function goAvePrev the only thing you changed?
Does your application in any way support debug tools like Firebug? It would be a real help if you could get an overview of the errors that stop the script execution. Also, in what way does this application that shows the help differ from a regular browser? And if it loads a browser in the backround, which one?
Without knowing what is going on, it's hard to tell what is causing the error.
Thanks very much for your reply. This customer issue was a real conundrum. I spoke with Adobe Support and per their suggestions, I experimented with new skins as well as the auto-created TOC. I also removed all Index and TOC entries and replaced them manually. QA dropped the various incarnations in the WebHelp folder and it looks like a combination of these efforts resulted in a stable help system. We have fixed it for the customer and will do another build of the next version of our product to make sure the help project appears and has a left pane of contents. So far, so good. At first, we got the help to appear without an error, but the left pane was blank. Now we have it working as expected.
Adobe mentioned that the upgrade to 10 might have corrupted the topics. We have found the whtbar.js file that we will always use for this particular WebHelp, and it looks like the other files are OK now. Thanks very much for the help.