Thanks to all for the answers
its CS4, my original project was on cs3 and I upgraded to cs4. and I was editing the project fine in cs4 also.
let me share this to you some how I manage to solve the problem by deleting newly added wav files because that was the only change I had made to project. still it didn’t worked for me, but I created again a new sequence after deleting new imported files and copy pasted old seq timeline to new seq. and it all worked fine then.
if someone can explain this solution, I just took a chance and I was lucky I feel.
the wave files were 48 stereo
project is dv pal 48.
Sachin Desai