Hi,
The pgis_outline data is in a projected coordinate system.
Extents:
minimum x = -18761
maximum x = 155
minimum y = -19586
maximum y = 6845
I tried GDBD2009 GEORSO, but that places the data in western Borneo, in Indonesia. GDM2000 MRSO puts it off west coast of Sumatra. GDM2000 Perak places it offshore, Western Peninsular Malaysia, so closer at least! GDM2000 Kedah and Perlis places it onshore, but in upper northwest peninsular Malaysia.
The way I'm doing this is adding the pgis_out shapefile to ArcMap. Then change the data frame's coordinate system to various possibilities (data frame property page, coordinate system tab, projected coordinate system, malaysia and singapore). If you have some base/reference data with a known coordinate system, that data will get projected to the new coordinate system. The data with no coordinate system will just be displayed. If you can get the two layers to overlay, then the data frame's coordinate system the one that the data with no coordinate system is using.
Melita