Installing X11 gives perl version conflict

[Dieter BSD]

RW> The problem as I see it is that he is installing packages that
RW> aren't built from the same tree. One of the dependencies of
RW> xf86-video-fbdev-0.4.2 was  built when perl 5.10 was the default
RW> and one after the default switched to perl 5.12.

RW> If building isn't an option then it's better to stick to one
RW> release trees at a time.

I think you are correct.  How does one stick to one release tree?
As I recall the CD/DVDs have a very small subset of ports/packages.
The ftp sites have the full set, but are not static.  Some packages
disappear, so you have no choice but to use a newer version.