Flash on Firefox 3.5

[Errol Sapir]

I have 2 computers using Kubuntu 9.04. My problem is with the adobe 
flash on one computer. On the computer with KDE 4.2.2 flash works 
without a problem. This is a 32 bit installation. The computer with KDE 
4.3 refuses to "activate" flash. This is a 64 bit installation Both 
computers were updated to use Firefox 3.5. What happens (on the KDE 4.3 
computer) is that I install flashplayer 10, am informed that the flash 
was installed correctly. When I reopen Firefox I still see the "missing 
plugin" message that requests me to install Adobe flash. I don't know if 
this is connected to the KDE 4.3 upgrade or to the fact that one 
computer is 64 bit and the other 32 bit. On both computers I upgraded to 
Firefox 3.5 at the same time, after I had updated to KDE 4.3 on the one 
computer. I have tried many ways to install Flashplayer 10, including 
various script written here:
http://www.cyberciti.biz/tips/install-flash-10-ubuntu-linux-64bit.html
On both computers when using Firefox 3.1 I didn't have a flash problem.
There are two major differences between the two computers which confound 
the problem for me.
1. The problem computer is 64 bit
2. The problem computer uses KDE 4.3
What can I do to try and solve this problem?
TIA
Errol