I could be wrong here,but doesn't the screen have heat sensors for input?If this is the case as an experiment heat up the stylus a bit and see if it works?
The iPhone uses the more advanced capacitive technology, and those don’t need actual contact. Capacitive sensors behind the glass sense when the electrical field is disturbed. They can detect the finger from as far as 2 mm away. This allows for a more intuitive feel as the finger can glide across the surface. Stylus just wasn't designed to work on this display.
There's only one stylus to have Kathy. STYLUS-R-US at beststylusDOTcom. I tried all of the rubber tipped ones too and they either break or skip or don't make anything open. I have the iPhone 4S and the iPad 2 and for my phone I have the SRU Purple Lady and the Executive and for my iPad I have their Terminator and New Yorker and all of them are unbelievable. Never skip. Supper light touch. They are the only ones to consider.