The new ICBM that failed during the test launch on September 27, 2011 remains a mystery - there is almost no reliable information about the missile. However, with the bits an pieces that are out there it seems likely that it was a reasonably new missile, rather than a modification of Topol-M/Yars. There were reports that the test involved a new transporter-launcher, which would point at a new missile. Some stories reported that the launcher (or, as the story says, the launch canister) was damaged during the test, so it needs to be repaired.
Also, some sources suggested that it was a small lightweight mobile missile, similar to the Kurier ICBM - it was a project that got to the stage of flight tests in the early 1990s only to be cancelled in 1991. I am a bit skeptical about the possibility of this being a small missile. A missile like this would have to carry a single warhead, which is not an option that would win MITT a lot of supporters these days.
If the source quoted by Interfax today is correct, we will se another flight test of the missile before the end of 2011.