Failed to detect cd drive!

Dear fellows,
the thing is ,iam trying to install suse 11 from cd when i re boot my system the welcome screen come and after that i click on installation .during configuration of devices when it waitS and show these lines…
creating device nodes with ude.
boot logging started on…
everything going fine till these lines
but then it shows
waiting for cd/dvd devices to appear…
Failed to detect cd drive!
and then system boot after 180sec…
kindly help me wat can be the possible reason?

Boot again and from the menu, run the media check option, it takes a while.