asterisk users - Dec 2006 - Cannot find ptlib-config, installing 1.4-beta3

Hi

When trying to install asterisk1.4-beta3 I get the following error when running
./configure:

"Cannot find ptlib-config - please install and try again"

What is this ptlib-config? Can't seem to find it on google. Where can I find
it
and how can I install it? Moreover do I really need it, can I force a bypass?

I have successfully installed zaptel 1.4.0-beta2 and libpri 1.4.0-beta1

Thanks.