Do this first
Flash Hard-SPL[CDMA]
Then download the ROM of your choice. I use the included "Custom_RUU.exe" as opposed to the older guides suggestions to drag the .nbh file to the RUU Folder.
This worked for me...flashed multiple ROM's on CDMA Touch Pro.
Oh...and updated winRAR has nothing to do with the success factor. Make sure you have .NET Framework 3.5