At least on Windows, it appears that Maya will do the variable expansion of %OUR_MODULE_PATH% in the first ("+") line. But it will not do the same expansion on the subsequent path and environment lines. So it finds the base path to the module given by %OUR_MODULE_PATH% in that first line, but all the subsequent uses of environment variables, like %OUR_MAYA_VERSION%, remain unexpanded and so the strings are not built as expected.

The documentation for module files doesn't seem to address this - is this correct? It is unfortunate that the variable expansion wouldn't be done for the entire file, as modules might have almost identical setups for multiple versions of Maya, differing only in something like a part of a path that could be controlled by an environment variable in this manner.