From: https://www.rabbitmq.com/install-windows-manual.html#install-erlang
RabbitMQ requires a 64-bit supported version of Erlang for Windows to be installed. Latest binary builds for Windows can be obtained from the Erlang/OTP Version Tree page.
Erlang will appear in the Start Menu, and \erl{version}\bin\erl.exe will be in C:\Program Files for 64-bit Erlang installations
Important: your system should only have one version of Erlang installed. Please consult the Windows-specific Issues page.
In case there's an existing RabbitMQ installation with the broker running as a service and you installed an Erlang VM with a different architecture then the service must be uninstalled before updating ERLANG_HOME.
Set ERLANG_HOME to where you actually put your Erlang installation, e.g. C:\Program Files\erl{version} (full path). The RabbitMQ batch files expect to execute %ERLANG_HOME%\bin\erl.exe.
Go to Start > Settings > Control Panel > System > Advanced > Environment Variables. Create the system environment variable ERLANG_HOME and set it to the full path of the directory which contains bin\erl.exe.
So i think you should make sure erlang is installed, the environment variable is set, and maybe re-install RabbitMQ.