So far I have not found any single help source that covers the entire product. I did try Axiom for a short period and they had a substantial archive of training resources, but I found there were some aspects of the software that were not covered at all. That was several years ago so they may have filled some of those gaps by now.
I also had access to Bentley learn for a couple of years and it was helpful for learning the basics, but again many aspects of the software were not covered.
I have yet to find any books that cover the product. Thus I have had to resort to reading the help files (which is a difficult way to learn), the Bentley Community forum & trial and error. I believe the reason there is so little support available is there are few in the private sector using the product and larger organizations such as DOT's provide in-house support for the users.
If you care to post your file I can take a look at it and see if I can find any problems. All I would need is your centerline element to test it. Before you post your file, try running the tool on it to confirm that it doesn't work for you.