What recovery are you currently using?
If it is stock recovery you will need to use the official google file and rename it "update.zip" and place it on the root of your SD card. Make you sure you visit the development section and read up on the procedures, as your radio version and recovery are not listed, its hard to tell from your post. If you are indeed in stock recovery...
Here is the original, official ROM http://forum.xda-developers.com/showthread.php?t=614057
, make you sure you load it correctly. And of course...I am not responsible for anything that may go wrong. You will soon get the OTA update to 2.2 Froyo.
If your on a custom recovery, you should download a custom ROM. Some are based on the stock AOSP so if that's what you want you can find one like that and flash it through custom recovery after the triple wipe (factory/cache/dalvik). If that doesn't work try switching to the other custom recovery image. Aman-Ra is one, ClockWork is the other.
Nexus One - Stock Rooted FRG83 Blackbar