Without knowing the exact format of the file - if the file is in a binary format, you shouldn't be pointing Splunk to read it directly. Splunk has no magic "decoding" of binary files, it indexes what it gets as-is. All you achieve by setting NO_BINARY_CHECK is to force Splunk to read all that non-readable data even though it doesn't make sense to do so.
What you need is something that will decode this data from the binary format to a textual representation of it, and then have Splunk read that output instead. Again, I don't know the exact format of this file that you're referring to, but some kind of flow reader would do this.
