The failure of the R-36MUTTH/SS-18 missile (in its incarnation as a Dnepr launcher) that was supposed to deliver 18 small satellites into orbit, reminded everyone that there are limits to extending missile lifetimes. The missile was launched from one of the silo launchers at the Baykonur launch site at 23:43 MSK (19:43 UTC) on July 26, 2006. According to Roskosmos, the main engine shut off at the 74th second of the flight. The missile's remains were found at about 150 kilometers from the launch pad in an unpopulated area of Kazakhstan.
There is nothing particularly unusual about failures of missiles or space launchers - these things happen. It is interesting though to learn the details of the preparation for launch. The missile is apparently one of the R-36MUTTH, produced in the early 1980s - their deployment was completed in 1983. This particular specimen was reported to have been taken out of service three years ago, after 20+ years of service. It was already a second missile chosen for this launch - the first one was withdrawn due to some technical problems discovered during preparations for the flight (which was originally scheduled to take place on June 28). This probably means that the customers of the Dnepr launchers would be more cautious about reliability of the missiles that the Rocket Forces offer to them.
I don't know what happened to the Rocket Forces plan to keep R-36MUTTH in service until 2007-2009, but this may be reconsidered as well. As for the R-36M2 missiles that are now in service (there are about 50 of them out of 70+ SS-18-class missiles), they are unlikely to be affected by this incident. These were built in the late 1980s-early 1990s and still have a few years before they will start to push that 20-25 years limit. But at some point they will.