@jeff thank you sooo so much, do you know how to avoid having all that bad geometry for future reference?
@pbacot how would I go about doing that?

😐 ...the same thing happened to us (in the company where I work) recently, shortly before we switched to SU2019 Pro. Not even our professionals from the IT department got VRay to run, although the demo clock started ticking anyway. At the end of the demo period, we all couldn't even test VRay for 5 minutes - too bad!
I'm not very skilled in installation routines myself, but the activation process seemed to me to be unnecessarily complicated - as i said, just my impression...

There are several plugins to join [or aka 'weld'] lines, curves, arcs etc into a single bound 'curve' object, these can then be used in processes, like those in some of my Extrude Tools...
My own version is available in the PluginStore.
http://sketchucation.com/pluginstore?pln=TIG-weld
Preselect a set of connected edges/curves, run the 'weld' tool from the Tools menu item, or setup/use a shortcut key-press... and then it should make a welded curve - but remember there can be no intervening 'branch' edges as these will split the curve where they touch it...