I have encounter between a Tzeentch Sorcerer and the PCs set for tomorrow. Now I'm considering giving the sorcerer the 'Flicker' spell on page 219. Basically it gives him the incorporeal trait (pg 141). It says normally an Incorporeal creature can't normally affect the corporeal world. However, I don’t think sending Doom Bolts would be limited by this power? What say you?

I have encounter between a Tzeentch Sorcerer and the PCs set for tomorrow. Now I'm considering giving the sorcerer the 'Flicker' spell on page 219. Basically it gives him the incorporeal trait (pg 141). It says normally an Incorporeal creature can't normally affect the corporeal world. However, I don’t think sending Doom Bolts would be limited by this power? What say you? 

EDIT: Sorry about the color above, I type in OpenOffice to catch typos and I forgot that it changes the font color.

I realise this reply is a little late, so I apologize, but maybe this will help.

With the Incorporeal Gift of the Gods, I believe that being Tzeentch Aligned allows you to use Psyker powers despite your lack of physical substance.  As you're using a Tzeentch Sorceror it would be fair to think that he would have that benefit.

The prophet of Tzeentch in the core book adventure also continues using psychic powers while insubstantial through flicker. However, he changes to exclusively using Tzeentchian mind-control, so you feel it makes it more fair, one could take the stance that any physical effect powers (TK, direct damage etc) can't be used.

That said, ask yourself this: how many of your pc's could actually strike against an Insubstantial enemy? This is, IIRC, exclusively something psykers and people with Daemon weapons can do. A fight against an untouchable opponent you can't harm isn't exactly fun.

From experience, a Tzeentchian Space Marine Psyker with a good spread of powers and Flicker is a nightmare to stop for anything but another psyker, and a pretty damn scary one even for them.

if you feel like balcning things out then slide a minor deamon weapon to one of your party members, using the rules say its boung at max strength so only one power and itsc  minor one so only a plas pistol with a horrow or damonette, will help enough thats its not so unstrung