"required CD/DVD drive device driver is not found" You have bad installation media (NOT related to the PERC/RAID) ... try any/all of the following:  
I have a 2850 that ran 2003r2 64bit. I want to upgrade to 2008r2 64 bit. I have followed all the advice but can not get the installation disc to go past the install now window. It goes to a screen asking for drivers. I have the latest Perc 4e/** drivers .It continues to try and load the driver but I get the error message "required CD/DVD drive device driver is not found". I cannot get to the screen that asks where I want to install the OS.
install windows 2008r2 on power edge 2850