I know a lot of people who have bug-bears with this machine have raised the issue about the slow responsiveness using the remote, but mine appears worse.

Yesterday I was watching a recording and wanted to FFwd the adverts, but the machine wouldn't respond, neither did the ReWind, or Stop. Only Pause button & Play seemed to work. Powered on/Off again, at it was Ok after that.

I also find that the machine doesn't alway respond first time to pressing the buttons. I have been patient enough to wait (upto 20 seconds) for the machine to react, but nothing happens until I press them again.
The main culprits for this appear to be the 3 main buttons above the cursor buttons, i/e System Menu, Title Menu & EPG buttons.
Also the eject button is another one I have to press more than once before anything happens. I also noticed that if I press the Eject button on the machine itself (from Standby) that the machine does not always eject, or power up first time round.

P.s Tried the obvious of changing the batteries

Hi Shredder, probably not your batteries, but the same problem everyone else is having with theirs, Check through the forum on personal DVD players and click on Sony for a whole list of problems with this machine which should be fixed with the next upgrade.