Hi,
I'm afraid "sometimes enougth space" isn't quite good enougth
for LaTeX... once it encounters ONE figure it can't place (and here
its a good idea to give LaTeX as many chances as possible i.e [htb]
instead of just [h]) it puts that fig. on the "float page" (usually
at the end of a chapter, if memory serves me). Of course, once this
happens, then LaTeX won't put following figs out of order, so they
get placed.....guess where?
Generic advice:
1) Specify [htb] instead of [h] to give LaTeX a decent stab at placing
in-line
2) Find the offending figure (i.e. first on the "float page") and
go and fix it (e.g. moving the actual \begin{figure}..\end{figure}
environment).
Hope this helps.
Malcolm Standring