Buggy Scroll Buttons in slideshow app

Question

I have no prior programming experience, and I am trying to
build a slideshow program for my site. I am simultaneously amazed
at how easy it is to do things I think are complex in Flex, and
frustrated at how difficult it is to do some things I think should
be simple or even built in. Most of my problems I have been able to
figure out from looking at examples of code similar to what I want,
but I haven't been able to figure out how to make buttons to
control my list of thumbnails.
I have a set of thumbnails loaded from a Flickr photoset in
an itemRenderer in a horizontalList, and I want to use buttons to
scroll through the list and to select different items in a
slideshow. On their own, the buttons work fine, but when I scroll
to the end using the fast scroll buttons, then select an item with
the cursor, the item selector buttons no longer work right--they
start skipping items in a weird way. I have attached the code I'm
using for the scroll and item selector functions. I have looked
everywhere for a solution, and tried many different ways of doing
this, but I am stuck.
So my main question is:
(1) what do I have to do to stop the buggy behaivor? Please
keep in mind that I have 0 programming experience, so please try to
keep your explanation as detailed and explicit as possible.
My other less pressing questions are:
(2) What do I use so that I do not have to type in the total
number of items in the list? EDIT--I solved this one myself, by
using maxHorizontalScrollPosition. duh.;
(3) is there an easy way to either have the list scroll when
the selector buttons select an item off screen, or have the item
selected item always be in the center of the screen? EDIT -- I
solved this one too using scrollToIndex(photoList.SelectedIndex),
after the showNext() or showPrevious() functions. It doesn't work
exactly the way I want, but close enough.
(4) can someone point me to an example of code that allows
the rest of the large images to be preloaded while the user is
looking at a particular photo, or some similar code I could use to
extrapolate how to do such a thing?
(5) would the buggy scroll buttons be considered a bug in
Flex Builder or is my code screwed up?

Answer 1

Well, here's the link to the application as it stands now:
http://www.dukeofclubs.com/acoustikzoo/
If it doesn't load at all, the problem is with my horrible
godaddy server, which I am in the process of changing. Just try
again later.
Changing the if(){} if(){} to if(){} else{} in the scroll
functions got rid of 99% of the problem. It went from being there
all of the time before, to now only coming up very very rarely,
usually when you scroll to the end very rapidly, then try to scroll
back.
Frankly, I'm not sure if it is a bug or not, because I am not
a programmer. Logically, "if, if" makes as much sense to me as "if,
else," but for all I know "if, if" is an invalid expression, and
that is what caused part of the problem. Similarly, I'm not sure if
there is something else in my code that is invalid that is causing
the remaining part of the problem. So I don't know if it is a bug
or not... you tell me--look at the scrollLeftFast() function, for
example. Should changing that from "if if" to "if else" make a
difference? If so, then the problem was with my code, else { I
guess there is a bug. }