It appears there is a version that started gaining momentum about 2001 shoot down of tu 154 which is - Ukrainians were using SAM system that didn't have at that moment a radar in the active mode that would have been needed in order to guide their missile to the target. Essentially - the target was supposed to be "lit" by the radar all the way from launch of a missile up until the moment of hitting the target.
On top of that the speed of that Ukrainian missile wasn't enough to reach Tu154 in time that was reported and found in the investigation.
However, there was another system that was used by Russian forces (it was a joint military exercise) with C300 and that system WAS capable of reaching the target in time. And on top of that, missiles of C300 don't require additional ground radar support.
It seems that back then the Ukrainian president took blame for Putin who was president of Russian Federation, since Putin didn't want trouble from Israel and whose citizens died in the crash.
I am not sure if there is version of the page that I came across in English - the original one was just thoughts of some blogger in Russian. Nonetheless if three of those things that he mentioned are true ( speed of SAM missiles, the need for the radar support, non-working Ukranian radar), then it is a legitimate version.
in Russian (unfortunately, can't translate it properly since it will take way too much time - try to use google translate instead)
http://magelanin.livejournal.com/3937025.html