In trying to install the new versions of Refactor! for VB and ASP.NET, I came across this annoying problem.
I was getting a very unhelpful "internal error 2739".
The first link above suggests re-registering JScript.dll.
I tried that to no avail.
But I'm running Vista x64, so I wondered if there were different versions of regsvr32.exe? A quick search of my \WINDOWS folder confirmed there are - in the \WINDOWS\SysWOW64 folder there's another version, and guess what - there's also a different version of jscript.dll!
So, I tried the following, then re-ran the installer for DXCore and Refactor, and success :-)