Hm I don't see a tmp folder in root or twrp. I did a search for all recovery.log files & only found the ones from 2.6.1 backups
I had to go back to 2.6.1 & got it to backup & restore.
I've attached one of those.
When trying using 2.6.3 it says it "Unable to create Folder: /external_sd/TWRP/..."
"Failed to make backup folder"
I am running TGG Literom 0.9.0