Well, at some point you are going to have to write within the batch file to cross reference a line of the log file that you are appending to to do "something" if the log file contains certain text like "FAILURE TO UPLOAD" or something like that.
So, you can accomplish that in a couple of different ways. You can incorporate a "find" step within your batch file or a "2 step" process that takes the elements of a text file... in this case, a log and then sets it into a variable and then use a IF THEN ELSE against the variable to do a certain task.
SET /P ERROR_MESSAGE=<SbxBackup_Folder_Create.txt 2>> SbxBackup_Folder_Create.txt
For instance, this is a line in a batch that I did a while ago. I have an error log for a SPECIFIC task in this text file and right before the text file gets deleted, I set the contents of it to the %ERROR_MESSAGE% variable...
from there I could echo it, recall it, dump it into another file, test it against an IF THEN ELSE, whatever I want.
But first things first, you will need to generate some test logs to find out:
1) What the errors are and when you get them
2) The exact verbiage of the errors
These are the key missing elements you need prior to doing anything else.