Hi roulisww,
Is that the end of the log? It indicates that more should have taken place later. But yes, concerning the main issue, it looks likely that it's running out of disk space. As explained in http://updraftplus.com/faqs/how-much-free-disk-space-do-i-need-to-create-a-backup/, when operating on zip files, PHP creates temporary files that it doesn't tell the program (in this case UpdraftPlus about) - so we need to do some clever guess work to clear them up. I'll try to get an updated version to you later that is more aggressive in the clearing. Can you just confirm that there's nothing more in the log file?
David