I've been the proud owner of an iMP-550 since not long after they became available. I purchased it with in the intention to use it to pass long traveling hours in cars quicker and it has been awesome, with sound and build quality that seem to rates high as it does on looks. But recently I decided to start taking it along on walks. Big mistake. I understand everything about 'not giving it enough time to buffer the song you're playing' but I barely make it two blocks with it in my back pocket, jacket pocket or in something it cant escape from for safe keeping before it starts skipping out of control. I even upgraded to 1.40 with hopes that '5. Other miscellaneous bugs have been fixed.' meant that some lingering buffering issue had been resolved. Sadly it still behaves the same. I've tried several kinds of media, burn speeds, my friends cd-r drives... nothing seems to help. Even some of the odder ideas I've seen floating around to deal with this, i.e. discharge/charge several times, etc. My friend who also purchased his same unit at almost the same time through buy.com, whom would be more trouble to deal with then to have the unit warantee'd through iRiver (if thats even possible.) *inhale* let me borrow it to take along with me and if it skipped twice, it was a lot. If anyone has any ideas on what I'm doing wrong or tips on dealing with iRiver to have the unit replaced or serviced, I'd be forever in your debt.