Are you using a physical disk or are you mounting an ISO in the drac? Will it boot straight to the installer if you put use the Windows disk directly?
Just a thought here, but the 2950's have a option of a CD or CD/DVD ROM options. Is it possible that you are trying to boot a DVD disc in a CD ROM only drive, you may want to eliminate this possibility.
What error are you getting? Like Admin4u said, make sure it is a DVD drive and not a CD drive.
When display message to insert dvd of windows server, insert disk press ok (disk burned of ISO ), and return message of not disk valid of windows server, this disk use other installations and install.
In SBUU section select operating system, select Windows Server 212 R2, x64, but description message only display Windows Server 2012 disk,
be possible to continue searching for the windows server 2012 only and not the windows server 2012 r2?
or who is looking for another label specific windows server 2012 r2 ?
What happens when you boot straight to the OS disk?