why is it you don't follow instrutions???
redsn0w has not been updated for 6.1.3 so you can't restore to it directly, you need to make redsn0w look at the 6.0 IPSW method while actually restoring to 6.1.3
so again:
DOWNLOAD 6.0 IPSW+6.1.3 IPSW
in redsn0w go to Extras/Select IPSW, select the 6.0 IPSW
now go to Extras/Even more/Restore and select the 6.1.3 IPSW
FOLLOW INSTRUCTIONS
it says exploit failed or says it needs to be in recovery mode even though it asks me to go into DFU mode