From the source distribution for R13B01, "README" file:
Portability
Erlang/OTP should be possible to build from source on any Unix
system, including Mac OS X.
Instructions for building from source on Windows are in the file README.win32.
Binary releases for Windows can be found at http://www.erlang.org/
At Ericsson we have a "Daily Build and Test" that runs on:
Operating system Versions
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Solaris/Sparc32 8, 9, 10
Solaris/Sparc64 10
Solaris/x86 10
Linux/Suse x86 9.4, 10.1
Linux/Suse x86_64 10.0, 10.1, 11.0
FreeBSD x86 7.1
Mac OS X/Intel 10.4.11 (Tiger), 10.5.6 (Leopard)
Windows XP SP3, 2003, Vista