Crashes when playing 1080 HD movies - current work around is clearing the cache

Hi,

I am currently having a few issue when playing HD movies (mainly 1080p but not limited to can also occur with 720) - basically what happens is sometime when i attempt to play a HD movie/tv show (it doesn;t matter on teh size of the file) XBMC crashes - i am using the SI02 skin and have determine that if i clear the cache and try again it works fine - i ahve also pin pointed this down to that it only occurs after a fair amount of media has been play - (ie the kids can watch a weeks worth of SD tv shows and then we decide to watch a HD movie and it will crash - which then i will clear the cache and everything will be working again - until the next crash) - originally i thought this was only related to the SI02 skin but i was able to replicate on confluence aswell - also it is is worth mentioning i am using apple tv2.

Does anyone have any idea of what is causing this or how to fix the permantly as this is easy enought to fix when i am in control - but when it is the wife or kids watching they don;t know that they have to clear the cache.

Any help would be appreciated

Cheers
jd