Rewire starts automatically. Just open a MIDI track in PT, then open astereo aux or audio track (until PT 7 where you just open an Instrument track) then in the audio/aux track pull down a plugin menu and select Instrument. Reason should be there. As soon as you click Reason Rewire will start.
In the MIDI track select the output to go into the right channel in Reason (whatever the sound you are using) if you want to trigger notes from PT.

Hope that helps.

Bas.

thank you, but that is my problem, there is no "reason" plug-in in there

That's strange.
Try installing Reason Adapted and reinstalling Reason.
That should work.

Good Luck.

Bas.

okay, there is no way to just install the part of adapted that I need? or do I have to uninstall reason, install adapted, then reinstall reason?

also, I've been reading on reason's web site that it has 64 channels in rewire but only the first 2 or stereo. Does this mean that if I want to track every different instrument in pro tools, they will all be mono, and I will loose all of my stereo effects?

What stereo effects? Do you know what you are talking about? Not all the instruments in Reason are stereo, you have to pan them from the mixer in reason and they will come out where you put them. Anything stereo from those channels will be on your stereo track in PT. Have you opened Reason yet?