@pushkan "All's Well That Ends Well" 
Re the batch file returned error code, by convention, command line execution should return zero when execution succeeds and non-zero when execution fails (so there is no actual error). If required, you can set these codes in your batch files.
I'm not sure to fully understand the second paragraph, but the reason I suggested to use the "net use" for a mapped drive is related to "impersonating" (do a Google search to learn more).
.... and if you want to also automatically exit your remote AmiBroker when the "scheduled batches" are done check the recently introduced command line parameters.