There is actually a simple fix to all the Vindictus issues. Apparently Nexon has been releasing the Steam updates through the beta opt-in instead of the regular way. If you opt-in for Vindictus beta updates that will get you current and working again. This could also been the old windows elevation issue. If it is that issue then you only need to right click on Steam and run as administrator when you open it. That issue should be fixed however when you update Vindictus by using the Beta Opt-in. One of the recent updates actually installs the version of the program exe with permission elevation required set.
To give credit where credit is due, here is the link to the original thread this fix was posted in and the quoted post: