Views_embed_view fatal error in views.inc
First thing I would try is using  instead of passing the arguments as an array. I recall hitting this issue because views_embed_view() uses func_get_args() to process view arguments and behaves oddly if an array of them is passed.

If that doesn't work, your best bet is to step through the code with Xdebug and see if you can find the difference between that variable when it works (all other times) and when it doesn't (this time).