...misread you slightly - thought you couldn't find the file since it wasn't saved successfully, usually forget to press the Exec button. :biggrin:

when making a flight plan using the built in FMC in the pmdg 737 and saving it, does it also save settings like the gross weight, fuel, payload, cost index, performance, engine, etc as well?

No, it will just save the route; you need to save the panel state in order to back up the parameters you're mentioning (along with every other switch setting in the cockpit).