In my case the swarm works ok most of the time, sometimes the administrator has to reset the dongle but we get it to work eventually. My problem is of a different kind. When rendering some materials that have a bump map, some of the render buckets are showing lighter than others. The darker ones are always from the host machine but usually one or two out of seven render nodes that we have are showing darker too.
I'm still not 100% sure if it happens with all the files/scenes/materials but we get that a lot. I tried turning on only the render nodes that rendered the same as the host machine but then again some of them render lighter. So far if I wanted to keep the bump maps the only solution was to render the scene on host machine only, but than we get a lot of render time for final renders. The other, more common case, is that I turn off the problematic bump map and render the scene without it using all the nodes we have...
btw...I use brute force for primary rays and light cache for secondary...
http://imgur.com/a/q9VDm

There is a solution for the bright spots. Under Settings/Color mapping tab uncheck "Sub-pixel mapping".
I don't have an answer for the IES problem. If your copy of V-ray is cracked maybe thats the issue, a bad crack...just saying...