What operating system are you using? Did you try the drivers located at http://www.vzam.net/vcastmusic/Step2...nufacturerID=4 ? Just click "Download" under any of those phone models as they all link to the same driver. A download prompt should then pop up. Do not worry about downloading any of the V CAST Music manager stuff as that is not necessary.
One quick note, I can confirm these drivers will work for the Intensity on Windows XP and Vista (both 32-bit and 64-bit versions), but they will not work on the 64-bit version of Windows 7 (don't know about the 32-bit version though)