Error when trying to install mods

[Kollidierende]

When I try to install modifications via the admin panel I get the following error:

You cannot download or install new packages because the Packages directory or one of the files in it are not writable!

When my package directory IS writable, the installed.list is writable too.

Can anyone help me?

[Rumbaar]

You might want to try a search for those terms in the search area, it's been asked a few times and the variance in answers that work are numerous.  If none of the threads offer a viable solution, please let us know.  But please try all options before hand.