Carsoft would be the easiest to use and can read/reset the airbag light on th E36/E46. Inpa works well and is more advanced but you need to know the model of the modules you are trying to connect to.
The cable in the link should work with your car. It's interesting that he hasn't mentioned what models the lead will work with as I suspect it would only work with certain models. You may also need a USB to Serial adapter.
The installation of the software is pretty involved. You'll need about 20GB of hdd space and will be installing VMWare configuring networking etc. I suspect that the CD supplied probably has a image on it for GT1, if not you will be installing and configuring a version of SCO Unix and setting up the networking to connect back to Ediabas running on your PC.
My advice if you were trying to reset the airbag light on the E46 would be to give the software in that link a go. The first part of the install would be to configure Inpa/Ediabas on your laptop and ensure that you can connect to your car before you install GT1. This should give you the ability to reset the airbag light. Once you have have done that, you can then have a go at getting GT1 going as it's a pretty cool toy!
An easier install for Inpa would be to use a Vagcom lead.