Ok found the reason and the fix. Thanks to the forums out there I was able to find the info.
for me it was droid x overclocker is what modified my build.prop file since i messed in the extras and changed things, durring the install of the new update hit search and you can see where it fails. Thats how i found out it was the /cache/blur_version.2.3.15.MB810..... failed authorization
All you need it a stock droid x 2.3.15 build prop, then paste it to the system folder using root explorer or simular file viewer. I restarted the phone, then clicked for the update search and let it do its thing, finally it installed all the way
Attached below is the stock froyo droid x build prop
Hope this helps someone else out