Download the 2010.7 version (KDE, Gnome, ... => choose it yourself - the KDE one is the standard one),
burn it to a CD as an .ISO, or put it on a USB-stick through UnetBootin for example....
Install it on your HD, run repository speed check, reload Synaptic, and Upgrade that installation
=> Then you can install additional applications from the PCLOS-repo without any problem!
If you want to stay using the PCLinuxOS 2007/09 version, you have to select the frozen repository from one of the forum members (but it's still not recommendable, because it isn't supported anymore!)