If I'm not missing something, your diagram will try and create a folder whose name is a single character, equal to the value of the 23rd byte in the data file. Since 1 through 8 aren't printable ASCII characters, I guess this might not work, and I assume the poster actually wants the folders to be named "01", "02" etc.
If this is the case, you will want to insert some code between the Read File and Build Path functions to convert the single-character string into the folder name. I'd suggest String to Byte Array, then an Index Array to get the first element (or you could use Array to Cluster with size set to 1, then Unbundle), then Format into String with '%02d' as the format string.