How do I convert videos for Samsung GT-i5503?

I'm using Samsung GT-i5503 with android version 2.2. I recently updated my Kies application. And after updating when I tried converting videos using Kies Video COnverter from youtube then saved in my phone, it won't play and error message was displayed(Sorry, this video cannot be played.). However, before updating my kies it works perfectly. How can I convert videos now so that can be played in my phone.