Magento Connect Manager not showing existing extensions

[Neju]

Hi,

I've Magento 1.7.0.2 installed. Problem is that when I go to Connect Manager it shows 2-3 latest installed extensions in existing extensions list. It is not even showing the Core Modules e.g. Mage_All_Latest, Mage_Centinel, Mage_Compiler etc. And I've to install Stitchlabs extension which have dependencies over core modules. And while installing it says Ready to install core modules and after proceeding it says Already exist. I am sure it is permissions issue but not getting which directory and files permissions creating this problem. I tried by changing downloader/cache.cfg and connect.cfg permissions but did not worked. Please help. Thanks

[iweb_smartie]

This is due to missing files in your var/package directory. If you check you will see the fiew xml files that relate to your most recent installations. Have you remove the entire var directory at any point?

[RashmiJ]

Hi, Is there any way to restore the var/package directory with all installed extension?

By mistake I deleted the folder and now I can check any updates.