I realize this is an old post, but I have some further information for anyone else looking for this in the future.
In my instance I had the same issue with my .bat file running fine from the command prompt, and from explorer, but not running from within my VBA code. I was attempting to run an AWK script to clean, and composite a series of .txt files before importing into a table.
My problem resolution lay within the AWK script. While it ran flawlessly outside of Access, the VBA script would apparently cause it to fail, perhaps a windows limitation when shelling out to run the command? The reason was, that my AWK script was dumping the resultant text file into the local directory, but the batch routine was going out to other locations for data. Once I edited the AWK script to explicitly include the drive and path for the output file, I had no further problems with the VBA script, and it ran fine. It also had no impact on manual execution of the AWK routine, so doesn't interfere with manual running in the future.
