Seems impossible to change default browser in a limited account (WinXP)

Hi all.
Bit of a convoluted enquiry so please bear with me.
I have installed "Crazy Browser"and it is the default browser (yes I
realise it is not strictly a browser in its own right and needs to be on top of I.E.)
for computer administrator accounts.However I want the kids on
limited accounts as they can not be totally trusted not to delete a
necessary file ,through accident,and I find that the lack of pop-ups
(have tried pop-up stopper was not any good for me, corrupted the running of I.E.),
which may have undesirable pics' for the kids,is a very good aspect of
"Crazy browser".However whenever I try to launch the 'net I am always asked
if I want to make CB the default browser,on the limited accounts, it does
not seem to matter what I tick on this question as following it a dialogue box tells me I have "failed to set data for " " note the single set of quotes.
Have set the kids accounts to administrator then it defaults readily
to CB but resetting to limited accounts seems to remove the CB default.Is
there anyway I can force "Crazy browser" to be the default browser on
limited accounts?
There is also a problem updating a Shockwave file on these limited
accounts ,no problems on the computer administrator accounts,have set then
as administrators site runs O.K. but on reverting to limited accounts update
is still required i.e. site will not run
url for site is. http://www.tv4.se/lattjo/kojan/bilbanan.asp
Obviously if more information is required or clarification just ask.I
think I have covered everything but....

Win XP (home) 2x computer administrator accounts 2x limited accounts
Crazy Browser and Internet Explorer