You missed my post, I think, in the thread that you started here: [www.hallofmaat.com]

There's an extensive amount of material on "Old Malay" and its forms and pre-forms. One older (1987) book can be found on Google:
[books.google.com]

Linguists have traced it back through roots and grammars to about 2,000 years ago. They usually trace cultural elements like art forms, traditions, music, musical instruments, deities, known names (royal and otherwise), and trade objects before stating that one language is related to another:
[sea.lib.niu.edu]

As you can see from this page, scholars have been studying the language since the late 1800's, looking at grammar forms and sentences and migration patterns: [w3.rz-berlin.mpg.de]

There are some arguments that Borneo is the mother home of the original Malay... this is an interesting page on it:
[epress.anu.edu.au]

-- but in the end, it really is related to Austronesian languages. The IndoEuropean ones you cite are a bit too young to have directly influenced it. The influences that you see come from more modern traders and conquerers -- the Portugese, Americans, English, French, Spanish, Germans, and the Muslims who are a dominant force in the culture and language. But none of them had any impact on the original language, which arose from an older Austronesian language.