Found this driver on HP's website. HP has this driver listed for the modem half of the Riptide Audio/Modem combo adapter. Even when extracting the files it states it is the Modem Drivers, However it is the Audio drivers not the modem drivers. Tested with Windows 2000 and works great.
File is Self Extracting. Once extracted, go to device manager, select device and tell it to search for driver, point it to the folder you extracted the files into, it should load, answer yes or OK to the Driver Certification page. Your audio should now be working fine.
This driver was only tested on Windows 2000, and do not know if it will work on other versions of windows. From what I can see this driver is hard to find. Once I find the Actual Modem Drivers I will upload them here as well.