The R12B release is from 2008. There was an update in how it handles ODBC libs in R13A, according to the readme file from that release:
The configure script of the odbc application now also looks
for odbc libraries in lib64 and lib/64 directories when
building on a 64-bit system.
This may explain why an older release is having trouble with locating the right ODBC library.
If you don't have any need for that specific version (and I sincerely hope you don't!), you should instead add the Erlang repository to get the current release:
wget http://packages.erlang-solutions.com/erlang-solutions-1.0-1.noarch.rpm
rpm -Uvh erlang-solutions-1.0-1.noarch.rpm
If you don't want do that, you could use the version in the epel repository is R14B, which is at least from this decade (2010 to be precise). To start using that repository, run
su -c 'rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm'
and then try installing erlang again.