Unable to install R-2.11.1.pkg and up to R-3.0.2 in Mac OSX 10.8.5
Why are you using the -store option? You realise that if you have that then -allowUntrusted is ignored. To quote the man page In this mode, no other options are supported. That option is there to check that a package is ready to be submitted to Apple for the App Store.

Take that out. 

I also discovered that failed attempts seem to leave orphan installer processes running that seem to cause trouble in later attempts - even a kill -9 leaves them on the process stack.

Reboot your computer and then run Terminal. First go sudo -s so you get an actual root shell. Now installer -verbose -pkg ~/Desktop/R-3.0.2.pkg -target / in the root shell. Thats what worked for me under 10.9