[HTC Aria Q&A, Help & Troubleshooting] ShinerDraft:
Here are the details of what I did to get my phone rooted. Hopefully this will help others that run into some of the the same issues..

The first hurdle was that I couldn't navigate to "recovery" on the HBOOT screen. The phone would not respond to the volume up or volume down buttons, and would boot into HDIAG. The solution to this was to simply remove the SD card. (See my previous post for more info)

So I navigated to "recovery" hoping that it would take me to clockworkmod. Nope. The guy that SOFF'd & rooted my phone did not install clockwork. I got the white HTC screen, and then a black screen with a red triangle & exclamation point over an image of the phone. The phone was trying to start the stock HTC recovery app, which wouldn't work without the SD card installed.

So I needed to install clockworkmod myself. Per Attn1's instructions, this was how: http://xdaforums.com/showpost.php?p=13650191&postcount=27

I installed the Android SDK which has the adb and fastboot tools on my laptop (Windows 7). (Note: The adb.exe and fastboot.exe applications used to be together in the "\tools" directory. In the latest version of the SDK, adb has been moved to the "\platform-tools" directory. This comes into play later..)

I turned on my phone, connected it to my laptop (charge only, usb debugging on), opened a command prompt in the "\platform-tools" directory, and typed "adb devices" to verify that my phone was connected. It was, so I typed the first command from attn1's post linked above ("adb reboot bootloader"). The phone went to the HBOOT screen. Things were looking good..

I navigated back to the "\tools" folder to run the next command ("fastboot erase cache") using fastboot. I got an error message that a .dll file was missing. I had a hunch that this file might have been moved to the "\platform-tools" directory with adb.exe. Yep, it was there. So I copied the .dll file to the "\tools" folder where fastboot could use it too. (Sorry, I don't remember the name of the file..)

I re-enter the "fastboot erase cache" command and got a response of "waiting on device". I waited a while, and the phone didn't do anything. The IRC folks said it was probably a driver issue, and it was. After a couple of hours (and adult beverages) I got it to work..

I installed HTC sync from this driver pack: http://www.megaupload.com/?d=LI4UVDDD

I followed these instructions: http://www.unrevoked.com/rootwiki/doku.php?id=public:windows_hboot_driver_install

I started all over again with attn1's instructions to install clockworkmod from the first step. I copied the "clockwork2501.zip" file into the "\tools" directory and everything went smoothly after that. I thought that I might have to uninstall HTC Sync, but I did not. Your results may vary..

So I disconnected the phone, and powered up to the HBOOT screen. The SD card was still out, so I was able to navigate to "recovery" which now took me to clockworkmod instead of the stock HTC recovery. (I did notice that the phone seems to still try to go into HDIAG. It doesn't respond to volume button navigation for about 5 seconds, then it lists a few files that it can't find on the SD card, then it goes back to the HBOOT screen where it does respond to volume button navigation...)

I powered back down, put in a brand new (larger) SD card, and put the FR008 zip file on it. Powered up to HBOOT, navigated to "recovery", wiped data, wiped cache, wiped dalvik, and then installed FR008 from the zip file.

Done. Finally.

Thanks again to attn1 and all the folks on his IRC. Hopefully this will help others who run into some of the same problems that I did.