see the first post in this thread.
ie. run the 2 commands in the first [EDIT] in this post:
http://linuxforums.org.uk/netbooks/install-firefox-4-on-an-acer-aspire-one-running-linpus-lite-linux/msg45901/#msg45901
Hi Mark
Those instructions don’t work for me. I don’t have an /opt directiory. This is possibly a reason why the other link I posted did work. However, check updates indicates that there is new stuff for firefox to download but system permissions deny their download.
bec456
you don’t have an /opt directory ?
yes you do… your own output (from the Firefox 5 thread):
[root@localhost user]# ls -al /opt total 16 drwxr-xr-x 4 root root 4096 2011-07-13 22:54 . drwxr-xr-x 25 root root 4096 2011-07-17 13:49 .. drwxr-xr-x 5 root root 4096 2008-06-03 18:29 Adobe drwxr-xr-x 12 root root 4096 2011-07-13 22:54 GKxdatacard
says you do 
You don’t have an /opt/firefox directory… which is to be expected, as the instructions you originally followed didn’t create one.
These instructions, or the ones for Firefox 5 WILL work for you… see my response to your posting in the Firefox 5 thread:
http://linuxforums.org.uk/netbooks/install-firefox-5-on-an-acer-aspire-one-running-linpus-lite-linux/msg60861/#msg60861
hi mark
many thanks for helping me to download firefox 4
with your help it was so easy, only took 3 attempts.
i’ll get used to ff4 then updrade to the latest addition.
made using the one a joy again.
thanks,
keith
Hi banko, and welcome to the forum 
Glad it helped, and thanks for the feedback.