This is the url to use:
It shows the source too.
In various order:
<br> is wrong,
Start of line 45 put a
<li>, and end of that line
Same for 122, but the
</li> must go before the
images/thumb-Screenshot_050830.jpg' /> incorrect
images/thumb-Screenshot_050830.jpg' alt="" /> correct
of course the alt should be the alternative text that would appear should the image not.
Most of the others seem to be list tags. They must follow this order
<ul> <----- just one opening tag
<li> <----- you can have lots of these
</li> <----- but they must match these close tags
</ul> <----- closes the list
Do some of that and see how many errors you have remaining ?