Ahhh... I've come across this before in Linpus Lite... it appears to be due to an incompatibility between the new
GoogleToolbar addon and Firefox 2 (as used in Linpus Lite).
Where you asked anything about a google toolbar when Firefox started?
The fix is to delete the
~/.mozilla/firefox/xxxxxx .default/GoogleToolbarData directory, and the
~/.mozilla/firefox/xxxxxx.default/extensions/{long giberish name} directory.
(where "xxxxxx" is a bunch of letters and/or numbers)
Or you could try starting Firefox in "safe mode" then deleting or disabling the GoogleToolbar addon.
(I haven't tested this method, so can't say for sure that it works).
First reboot your PC (to kill any already running firefox processes), but when it starts, DON'T attempt to open Firefox normally... insted, follow these instructions.
To open Firefox in SAFE MODE...
Hit
Alt+F2... in the resulting dialogue (text) box enter:
firefox -safe-mode now click the
Run button.
(don't miss out the space between the "x" and the "-", and it MUST be all lower case)
In the resulting dialogue, put a tick in "
Disable all addons" (or similar)... then click "
Continue in safe mode" (or similar).
Then if Firefox starts... Go to
Tools>Addons>PlugIns (or Extensions), and delete or disable the GoogleToolbar plugin/extension.
Close Firefox, and restart it normally.
It *may* be better to
disable the addon rather than delete it, as it *may* get reinstalled if you delete it... but that's for you to discover, I haven't got an AA1 so I can't test it.

[EDIT]
for a more complete set of instructions, see here:
http://linuxforums.org.uk/netbooks/acer-aspire-one-linpus-lite-firefox-web-browser-wont-open/