I was re-installing Visual .Net 2003 yesterday and the installation went smoothly only after to get to it it came out with the error:-
Dte.olb could not be loaded.Please re-run setup and repair your installation
I said to myself another hours of installtion but before that i decided to look out for the cause and i found a solution 
on Shannon's site
The problem was that the file which is a COM oblect didn't register succesfully
So what you just have to do is to re register by doing:-
regsvr32 "c:\Program Files\Common Files\Microsoft Shared\MSEnv\dte.olb" make sure you add the quotes.
And that did the trick and worked like a charm and saved re-installation.