I believe you will find the answer in the manual(s) you received with your Acer server: the lights are purple because you haven't yet completed the "out of box" setup, which you will do the first time you install the client software.
There's a lot of useful information in those manuals, as well as the help files, the Microsfot web site, etc. It's well worth reading all the documentation available.
I'm not on the WHS team, I just post a lot. :)