I've noticed incompleteness in the Makefile of Erlang source-tarball package in R12B-4 version.
To build Erlang system from the source files, under CentOS 5 environment, additional library option is required.
for details, you can see Peter Lemenkov's post to erlang-questions ML.
or, if you are can read Japanese, refer my blog in Japanese.
Here is the patch for the "lib/ssl/c_src/Makefile.in".
Still the bug exists in R12B-5 version of Erlang (latest as of today).