Cannot install packages

I am having problems installing packages with 'Target directory is either not a directory or writable'. I have set all permissions to 777 and everything else, no joy. I do suspect there is another problem, though, as I don't get any readme or licence info when I try and install. Can anyone point me to what else I can check?
- paths exists
- files are downloaded
- permissions are there

??

Thanks

The installer has to be able to create new directories like assets/components/newcomponent and /core/components/newcomponent/, which it can also write to. So if new directories are being created with the wrong permissions, then the installation cannot continue.

thanks for your reply. Both directories are writeable already, and even setting them to 777 doesn't make a difference, plus the message that comes up is not complaining about those directories. Exact message is:

Target directory is either not a directory or writable: /home/sitepath/public_html/core/packages/
Package found...now preparing to install.
Attempting to install package with signature: getresources-1.6.0-pl
Could not install package with signature: getresources-1.6.0-pl
Could not transfer package getresources-1.6.0-pl.transport.zip to /home/sitepath/public_html/core/packages/.

Any other ideas?

Check your server's PHP error logs.

I have, nothing in there

Did you check ownership of the core/packages/ directory?