If you try to install Proseries in any directory except C:\ProWinYY (where YY=year), then your install will fail with "There was a problem installing Entitlement Client".  No one in support will be able to help you because they claim there is just some problem with your computer hardware or operating system.  I believe it is caused because the Entitlement software has this particular directory hard-coded, so when it tries to read from itself from a different directory, it can't find itself.  This has been a problem for several years and has cost me a lot of time to figure out.