I'll apreciate if someone coul offer some kind of trace about this
problem

Testing MOSS 2007 i've created tow identic Portals.

In the first one, surely i've done something bad as i'm not long able
to create content types inherited form Sistem Page Content Type
(Article Page, Wellcome Page,...), for i'm able to create other
content iherrted from diferent types (i.e. Web Part Page). I'm just
able to solve this problem and create whatever if i'm site colection
administrator.

I've created the second one just to compare, securuty, content types,
if've checked settings and son on, and i can't collect any information
or anything. No idea.

The error is simple: access denied

What's your opinion: is it about content types, about permissions,
which setting should i check

Thank and best regard