I assume you rooted your phone yourself, so you should have in your computer the Android SDK, right? if so, inside the SDK installation there is a "Tools" directory which has the "adb" tool. Check this thread before you do anything else on your phone:I have no idea how to use adb. What is that exactly. I did a google search and it looks to be developer software. Where can I download it? I would really like to install the htc music apk's!
How 2 - ADB, Rooting(reflash), Unrooting, Nandroid, Remove/Install App, roms, kernels - xda-developers
The above thread shows you how to use adb for simple things like uninstalling apps, etc. Similar commands are used to copy the HTC Music apk into your phone.