How would I go about making sure when a file is uploaded that it just won't keep over writting itself?

This is the code on upload

Code:
 Inet1.Execute , "PUT  ""c:\Windows\errors.txt""" & "errors.txt"
Let's say I want it to upload as the following:
errors
errors1
errors2

Pretty much just keep increasing the number the txt file won't keep overwritting itself.