Jeepster - could you tell us when this error occurs please? Do you get to see the title screen? Select a char maybe? Or even get into the game, then crash?
This could be potentially be a tricky one. "Runtime Error" failures are generally either the game doing something it shouldn't (I've had a couple of game crashes with a runtime error), or an old version of the C++ runtime being installed. If you've re-installed Ryzom several times, I'm thinking it's more likely to be the C++ runtime giving you problems. As a quick test/potential fix, you could download the following directly from the Microsoft Download Centre:
Visual C++ 2008 Redistritbutable Package
This is the latest version, and will hopefully do the trick. If you prefer to visit the MS site and find this file yourself (link paranoia
hehe), go the download centre and use "c++ runtime" as your keywords, then download the package I described above.
I don't think you need to restart once it's installed, but do so if it prompts you to. Then try running Ryzom again. If you still get the same runtime error in the same place, that *should* rule out the runtime system itself, and point towards Ryzom misbhevaing for some reason. That will require more testing/thought to find an answer, but there are plenty here who can help out
Eliminating the runtime itself is probably the first step you should take.