[solaris] How to get rid of the "No bootable medium found!" error in Virtual Box?

Follow the steps below:

1) Select your VM Instance. Go to Settings->Storage

2) Under the storage tree select the default image or "Empty"(which ever is present)

3) Under the attributes frame, click on the CD image and select "Choose a virtual CD/DVD disk file"

4) Browse and select the image file(iso or what ever format) from the system

5) Select OK.

Abishek's solution is correct. But the highlighted area in 2nd image could be misleading.