If you can't make it whatever you try I've got a savegame file for you.
First make sure you have the Update 1.2 installed. If not, go get it at ftp://ftp.lucasarts.com/patches/pc/J3DUpdate1.2.exe - you'll get an EXE file which you simply double-click, it installs itself.
Next, download the babylon-radiotower savegame from my ftp server. There are two files at ftp://ftp.soulianis.com/archive/indy/ - the original savegame (.nds) and a zipped version (.zip) - you need WinZip or pkunzip for the zipped version but it is much smaller and therefore you save a lot of download time.