Cannot run Sun Blade 1500 CD-ROM

When I put the Sun Blade 1500 (Silver) documentation CD-ROM in the supplied DVD-ROM drive, it waits for a few seconds before spitting it out again. Anyone know what's wrong?
[195 byte] By [m0thr4] at [2007-11-25 23:07:18]
# 1
Is this only with the mentioned CD or with every CD that is inserted?
mlennon at 2007-7-5 17:58:21 > top of Java-index,Sun Hardware,Workstations - General Discussion...