Amit - The one that was missing for me is called mod_expires. The other ones required, at least that I can find, are the Apache mod mime and mod rewrite modules. There's a lot more information in the
WP Super Cache installation instructions. Edit: Even if the modules are missing, you can use the functionality that WP Super Cache imported from WP Cache, so either way, you stand to gain some benefit from the plugin.
yogesh sarkar - Whether or not you need to edit certain files seems to turn out differently for different people. I had to edit or create quite a few different files, even after changing my file permissions, and it's a common enough issue that they tell you what to do in
the faq section for the plugin. Whether or not Amit will need to do as much editing as me, I don't know, I just thought it would be good to know that there are different ways the installation could go and be prepared for it.
Either way, any editing involved isn't a big deal, just copy and paste stuff. I just made a mess of one of the files by accidentally deleting something while I was doing the pasting. Should have been a bit more careful there, but hey, that's what the backup was for.