I downloaded the last version 3.x.x  about 2 weeks ago.  Started the game and it logged me into the world fine.
Release 4 came out I downloaded it and installed it into the default location over the orig. installation of ver. 3.x.x
Client did not run, read the forums and saw that it was bad to install over the previous install...so I deleted both, deleted the downloaded file off of my computer and re-downloaded the game.
I installed it under program files at the default location and it did not work.  Once again I deleted all files from my computer and re-downloaded it once again to install i cleanly at c:/planeshift steel blue
I ran the updater as administrator and it worked.  But the client nor the setup will not run.  I have tried running both as adminastrator but still receive error at startup.  this is the responce that I get:
EXCEPTION_ACCESS_VIOLATION AT 03398D40
followed with:
"psclient.exe  has stopped working"

I am running a laptop with 2 ghz
amd64
2gig ram
plenty of hard disk space
128 mb vid.