What's the exact model number of that Acer Aspire?
I would like to look up that model at the Acer website to learn more about exactly what you have.

What leads you to believe your operating system is Android and not Linux?
AFAIK, Android is for mobile phone type devices, but there's no real reason reason that it couldn't also be used on a netbook type device. But it is my understanding that Android doesn't support NPAPI plugins which Firefox uses, which IMO really limits it usefulness on a netbook. I have an ASUS EeePC 900 that is currently running a version of Ubuntu that is made specifically for Netbooks like the EeePC and the Acer Aspire.

And as far as Moblin goes, I wonder if that still an active project?
http://moblin.org/downloads
http://moblin.org/projects/moblin-core
The latest version was released well over a year ago.

Android is also used plenty on Tablets, MIDs, PMPs (without wifi) and even Netbooks. It is not just for phones.

Anyways there was this from Nov 2009. Unboxing Acer Aspire One Android netbook http://www.youtube.com/watch?v=U1e0q2DYAd8

Some of these models came with Android 2.1 and uses 10.1" Ultra-Thin D250 .. WinXP and Android 10.1" Ultra-Thin D255 .. WinXP and Android 2.1 (said to be half-baked) 10.1" Ultra-Thin D260 Atom N455 or Atom N450. Windows 7 and Android.

Acer Aspire One Happy 10" uses a Intel N550 and came out in November 2010. It dual booted with Android 2.1 and Windows 7. http://www.engadget.com/2010/10/12/acer-goes-pastel-with-10-1-inch-aspire-one-happy-dual-booting-ne/

As for NPAPI plugins. https://support.mozilla.com/en-US/questions/781539 Firefox for mobile does have code to support NPAPI plugins, but it is disabled by default and not fully supported.

To enable plugin support, go to the "about:config" page, then search for "plugin.disable" and change the value to "false."

On Maemo and on desktop operating systems, you can install plugins by placing them in standard locations like /usr/lib/mozilla/plugins.

I don't know whether there's a way to install NPAPI plugins for use by Firefox. (NPAPI plugin support is completely untested on Android, and may or may not work at all.)

Try going to http://www.mozilla.com/en-US/mobile/

Or even to https://wiki.mozilla.org/Mobile/Platforms/Android

But even if it has Android 2.1 it may not have been ported very well and the cpu on wherever netbook may not be compatible with current mobile Firefox Releases from Mozilla.

Yes, that's the acer I have. The "about" shiretoko reports: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.3) Gecko/20091022 Moblin/3.5.1-3.15.18.moblin2 Firefox/3.5.1. The linux download from the mozilla page can't be opened by android.

I linked you to the Android version not the Linux version as the Linux version will not work on Android.

However it seems like you are using Moblin, not Android?

Thanks. The limited documentation says android. When I went to the mobile download page http://www.mozilla.com/en-US/m/beta, the link for android wasn't a valid http:// address; instead it points to market://details?id=org.mozilla.firefox. (?)

I'd assume the original poster has the same as me (well, my daughter actually): http://www.acer.co.uk/ac/en/GB/content/model/LU.SE80D.004

i.e. Aspire One Happy - 2DQpp ( LU.SE80D.004 )

It is in fact running Android OS - however Firefox reports the slightly misleading 'moblin' tag. Then again isn't Android based on Linux?

I am having an issue with Firefox not able to find any web-page on this one - the 'Android built in' browser works fine... Any ideas appreciated?