Get the shambala_clockwork´savegame file(s) from my ftp server at ftp://ftp.soulianis.com/archive/indy/ - I provide each as original (.nds) and zipped (.zip) variant. The .zip variant requires WinZip or pkunzip but is much smaller and saves you some download time.
The _1 file is immediately before jumping the lower moving platform. The _2 file is after reaching the exit gate above.
Note that you require the Update 1.2 for these savegame files. If you don't have it, 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.