I am also fairly new to soundTap, but am prretty familiar with the rest of Win XP. I use SoundTap with RealPlayer and have no problems recording from anything - CDs, LPs (thru an iMic USB digitizer), and online radio streams. I have captured as much as 6 hours continuous with no problems (except for some VERY lengthy editing to remove all the individual songs and name them + add the artist).
I seem to remember when I first was thinking to buy soundTap that I saw somewhere on NCH's website that it mentioned "working with ....RealPlayer..) along with others. Since that is what I use for default anyway, no problems.
My system crashed out on me a couple of weeks ago and I had to do a 'repair' reinstallation, which cause me to lose some drivers. After this SoundTap wouldn't save the recordings right. But another forum entry had the same problem and NCH advised him to download and install an MP3 codec, which I did, and that fixed me up.
I would suggest you try to Use RealPlayer as your default multimedia player on your PC. It has some nice spacey/psychedelic 'visualizations', too.
Hope everything works out okay, nothing more frustrating to find the progrma that is exactly what you want and not have it work right. But SoundTap seems to be pretty stable to me (I found it on a 'Best Shareware/Reeware' newsletter I get every month.