If they specify a 200MHz CPU as minimum reqirement they should have verified that. However, I think it's possible that if you have nothing more than the minimum CPU requirements it is more likely that other components of your system (graphics card, ram) become more important than if your CPU would have more power.
Nevertheless, 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 savegame which I put on my ftp server for you. This will enable you to overcome the problem. 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.