Playback through Computer speakers?

the reason is probably because cool edit pro was not using ASIO or WDM drivers. When you are using Directsound or WaveOut drivers, you can use whatever input output configuration, but the options afterwards (sample rate, number of tracks) might be limited, as you found out. In reaper, you can switch to using WDM drivers which might solve your problem, although they are not as stable as ASIO. please go to your audio device settings (upper right hand corner of reaper, click there) and change the driver type to WDM and you will see different options: hopefully someone else can come and shed some more light :) also check out: ASIO4ALL

Not familiar with the Firestudio. Nearly bought one once 

Presumably there is more than one out on the Firestudio or you could split it and then if the computer speakers are active do as TerrorGasm suggests. If the speakers are passive just a cheap amp or one borrowed will do. Some of the best music I have made is using computer speakers. It has had to be cleaned up and the bass, particularly adjusted later using monitors but I firmly believe that you can make the feeling and rhythm of great tracks on lo fi gear and that those are the substance. I actually prefer some of the live tracks of the old band to studio versions which are sonically way superior but have a clinical feel compared to a room full of drunken yobs and relatively crappy sound. Oh and G'day Jason. It has been years I think. Spose marriage to the most wonderful woman in the world (for me) makes me neglect the Reaper forums.

You could also plug your computer speakers into the headphone output of the firestudio. You may need a 1/4 to 1/8 adaptor to do this. I'd try getting a combiner adaptor first as JBM suggested. But using the headphone out can work until you get the adaptor.