I'm afraid I can't replicate this as my 11.8 is only licenced for "normal" use, not for batch/script automation.
It sounds like you might be running a regular model against a filename that changes, so it might be worth considering upgrading to Datawatch DataPump/Automator/Server so that you could use wildcard filenames.
If you are forced to run the automation on a desktop, then there are other experts here who might have creative solutions.
I can't test this to my satisfaction with Version 11 either but will comment nonetheless.
When using 'simple' DOS batch files, I commonly built verifications into them that checked for the existence of required files prior to the point where the batch file executes the project. For this, I used the "[B]IF EXIST[/B]" command. If the files didn't exist, the batch file could prompt a number of options; with one of the options being to cancel the execution of the batch file altogether.
2 other options available in a DOS batch file are:
the CHOICE[/B] command can be used when the file required varies among a defined list of filenames. In this context, these filenames would typically be presented to the user in the preceding lines of output displayed by the batch file.
/C[:]choices Specifies allowable keys. Default is YN.
/N Does not display choices and ? at end of prompt string.
/S Treats choice keys as case sensitive.
/T[:]c,nn Defaults choice to c after seconds.
text Prompts string to display.
/CODE[INDENT]While the use of the CHOICE[/B] command (and its subsequent ERRORLEVEL[/B] response determinations) is appropriate in many cases and affords a desired level of 'user-proofing' the responses keyed by the user, I sense that the following option may be more to liking of some...[/INDENT]
For many batch file generators desiring a generally more versatile or liberal response from the user, the SET[/B] command with a '[B]/P[/B]' command switch should satisfy that requirement. It will prompt for user-keyed input (including typos) and assign it to a variable that can be used throughout the batch file.
[B]SET /P /Bvariable=[promptString]
Please note: You may need to include commands in the batch file so as to change the filesystem directory wherein the batch is looking for the existing or prompted filename relative to the location from where the batch file is executed.